Introducing Big Juicy

Wrestled with stereos today. The PO put a Kenwood unit in but I never got sound out of the fronts because they were blown. Wife got me new fronts, which got me noises on the front right, but front left still had nothing.

I did a continuity test on the wires at the speaker & the radio side of the harness, and put a 9V battery across the + & - wires at the harness and got noise to come out of the left speaker. So the speaker works & no wiring issues.

Finally got serious about things and decided to check the signal on each output wire. In a perfect world I’d have an oscilloscope, but here in reality I just have my multimeter. Using my brand new el cheap-o back testing probes I was able to determine that the head unit is sending signal on all 8 wires but I lose the signal on one of the front right wires sometime after the ISO plug.

New plug will be here Tuesday. I don’t love spending $10 on a deck I hate, but I’m not ready to drop the cash on a new head unit just yet.

Speaking of new head units, a guy on FB marketplace was selling a Chinese double din CarPlay enabled unit for $40. It was worth the gamble I figured.

But maybe not. Wired it in, no sound on the rears, which could just be that the wires are incorrectly labeled in the manual. A friend also bought one of these and both units had the same results.

But interestingly no sound on the front left again. That would suggest that the wiring that is common between both units is the issue, but I believe I’ve tested that and shown it to be ok.

So IDK. I’m not sure how to test which wire is ACTUALLY which aside from trial and error. I didn’t back probe the unit, I guess I need to do that next.

When I cleaned up the wiring at the radio harness a while back, I opted to connect everything with spade terminals because (a) I expected to have to disconnect it multiple times while I sorted out the wiring and (b) I hate soldering anyway. This was handy while I was testing the 2 Chinese radios but also my Kenwood. But also a pain because the quick disconnects aren't always super quick.

So I decided to work smarter rather than harder, and I put the radio on the airbox in the engine bay and got to work. Jumpered red & yellow and connected to +12V on the battery. Similarly grounded it, and then used my alligator clip/probes to connect pairs of speakers. First up, the new ISO plug on the Kenwood had sound on all 4 speakers. So that mystery is solved. Jump cut to the end of the story, I put the Kenwood back in and now have sound on all 4 speakers. The astute reader may recall that the PO had two shelf speakers wired in on the rear shelf thingy and no other speakers worked. So this is a major victory.

Then I checked out the Chinese decks. Same process, only got output from the front right set of wires. Learning from the prior paragraph, I did a continuity test on that pigtail, and sure enough found that only that one pair of wires had continuity from pin to strip. Since we had two identical radios, I did the same check on the other pigtail and sure enough it passed all the tests. I plugged it in and repeated the speaker test, got sound on all 4 speakers. Swapped radios, it passed as well. So the cheap radios appear to be functioning save one garbage harness. Looks like the seller is going to swap me a new harness (which I will continuity test on the scene), so we should be good to go. The radio itself might be garbage but I like my odds on a $40 gamble.

Once the radio issues got resolved, I started to think about my accessory switching. With the relay box in place & trigger wires run to the cabin, the next step is to figure out exactly how I want to wire it all up. I want some switches to be independent of the key (like light pods) and others to require accessory (like future e-locker). I also think I want LED tipped switches, although those operate in one of two ways: either the LED is always on whenever one side has power, or the LED only comes on when the switch is closed. I want the LED to be always on, but only to come on with the key.

I had an epiphany about relays. First, they aren't black magic. Second, they really only do one thing (assuming you're using a Bosch style relay): They tie pins 30 & 87 together whenever pin 86 has power and 85 is grounded. So think of 85 & 86 as completing a circuit that is probably controlled by a switch somewhere. When you throw the switch, whatever you have on pin 30 will pass through to pin 87. Typically that is where your battery power will pass through to your accessory.

Now the LED switches I have will only light up with the ground pin on the switch grounded, so no ground, no light. Here is where I'm pretty proud of myself. I added a relay to control the ground based on the presence of accessory power:

"LED/ground" relay
Pin 30: chassis ground
Pin 87: ground pin on the LED switch
Pin 85: chassis ground
Pin 86: switched +12V from the add-a-fuse off the radio circuit



Here is the relay wiring in the relay box
Pin 30: +12V from battery
Pin 87: +12V to accessory
Pin 85: chassis ground
Pin 86: switched +12V from passenger compartment switch powered by an add-a-fuse off the radio circuit. Constant power will be supplied by an add-a-fuse off the fog lamp circuit. (Some accessories will require power w/o the key, some I want to turn off when the key goes off).

So now the light pods turn on with or without the key, but the LED on the tip of the switch only comes on with the key in accessory/on/run. That is definitely what I set out to do....whether or not it is actually what I end up wanting is another story. It's dark in the jeep at night and I don't want to fumble looking for the light switch is my main motivation for this setup. I probably could've tapped into the dash illumination circuit but I really don't want to cut into that wiring (or any wiring for that matter) if I can avoid it. This keeps all the wiring right at the switch box at the cost of one relay....with the added benefit of I feel like I finally get relays now.

I need a switch panel. Ok, I want a switch panel. I’ve always wanted to DIY one, but I’m not sure my fab skills are up to the challenge. I wanted something from 12VoltGuy but he doesn’t like to respond via any channel and his stuff isn’t cheap.

Then I found a blog post from 14 years ago where the author showed a few key pictures that showed me how it was built. Ok fine, I’ll attempt this myself.

Started by mocking up the 2 mounting ears out of a cereal box. Once I had it close I transferred the measurements to a piece of sheet metal and got to freehand cutting with my cutoff tool. Not ideal, but it’s what I had. Then I got to use my cheapo HF bending brake for the very first time to make the bends. Those turned out great, but I can see how a better tool can make sharper bends. These will work.



Anyway, I got to this point tonight with about 3 hrs of slow labor. Cutting, fitting, trimming/grinding, fitting more, etc. need some mounting hardware, paint, and to figure out how I want to lay it all out. But I’m pretty impressed with what my 3 hours got me.

The steel I used was a 26ga sheet from Home Depot for like $6. I think it will be sturdy enough? Drilling the holes required some caution; they're near the edge and the drill press definitely wanted to push the metal down into the hole in the table since the part didn't span the hole. I probably should've used a wood backer for support. I will definitely do that when I cut the switch holes..

The hardest part was figuring out the dimensions, which was a lot of (and continues to be) trial and error. Cutting with a cutoff tool is a little imprecise too, I may pick up a bandsaw to make the cuts more precise if I decide I need to improve on this prototype. I'm sure 12VoltGuy has these dimensions down to the thousands and has them laser cut or something.

TJ Starting said:

Excited to see how yours turns out. I've found too that it helps a lot to use a plywood backer or somesuch when drilling thin sheet metal were it matters

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It’s been 25 years since I did any fab work, and that was usually on minimum 1/4” aluminum plate or round stock. And I had access to an old South Bend lathe, a milling machine, etc. We had an upright bandsaw (similar style to the woodworking bandsaws at HF) but we cut aluminum plate on it all day. I don’t know if we had a special blade on it or if it was designed for metal (slower speeds) but I wish I had that in my garage.

Anyway, learning as I go as usual. This won’t be perfect but it’s better than $200+ and an 8? week lead time buying from 12VG or some Etsy shop.

Steel: $6
Switches: $12 for 5 led tips
Power: $6 for a 12V socket & I already had a dual USB voltmeter combo thing.

So basically $24 + stuff I already had (tools, paint, etc)

Where to start? Laid out where I want my switches & stuff, then got to drilling. I have 2 12V/USB outlets that require a 1-1/8” hole so I used my step up bit. It took a long time, and I had to use the smaller step up bit which goes to 7/8” before I could switch to the bigger bit. Having a wood backer there does not work, but I didn’t bend anything w/o the backer.



I had some switches left over from another project so I threw what I had in there, knowing I was only wiring up 2 of them for the time being. I have some purple LED tip switches coming next week.



From there I wired some of it up, daisy chaining the power & ground as I went, although only the outlets need a ground currently. That’s when I realized my haste to get it “done enough” this week caused me to overlook that the 12V outlet has an ambient LED and since I only ran one power feed off a constant source it was going to be on all the time. I removed the ground from it for now, will run accessory power next week.

Then I put the HVAC control back in. First, I broke part of the upper mechanism that controls which vents are open but it looks to still work. . Then I struggled to route the heater control cable which apparently is much easier to do before you put the dash back on. Managed to not link it. Also could not get one of the light bulbs to seat so no lights on the fan speed side of the control now. I hate when I make something worse than when I found it, especially on a part I didn’t even need to touch.

Then I mounted the switch panel & new bezel. I’m a little sad with how the heater control is recessed. I could add some spacers but I’ll need to get longer screws.

Switch panel looks good for now, still needs paint, the correct switches, and minor tweaks. Like the 12v outlet is going to not work in that spot thanks to the shifter.

Also still need to wire in the wiper & defroster.



Overall I’m pretty happy. I’ll like it more with paint.

NashvilleTJ said:

Nice work - looks good.

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Thanks, I'm pretty pleased esp given the quality fab tools I have and the fact that I'm pretty much making it up as I go. I did realize that I need a better drill press and man would I love a milling machine. I've really never thought "man, I could really use a drill press right about now" but I've used the drill press pretty much nonstop since I got it (for free) a few weeks ago. It's the cheapest Harbor Freight model, and it's not a precision machine.

The mill would've been great for this, getting the holes exactly right, cleaning up the edges and making everything square. But even the cheapest HF mill is $800, so that ain't happening. Although I figure once I have one I'll suddenly have all sorts of things that require it.

I worked in a machine shop in college where I got experience on this stuff, I would love to get my hands on that old post WWII-era stuff like we had. I keep trolling CL & FB marketplace but haven't found as much of that sort of thing as I hoped.

Going wheeling this weekend so I needed to start getting everything back together & actually put some miles on it after all this electrical work. One thing I've been putting off is the torque converter lockup plug. I've proven that if I plug it in the wrong way, I blow a fuse. Now I've proven that if you plug it in the right way it will not only not blow any fuses, it will actually lock up the torque converter in 3rd gear! That's a major success, and it does prove that the solenoid at least partially works. I only drove it about a half mile (doors off, and it's in the high 40's today) but I saw it lock up twice. CEL is still on with a stored P0743 code, but I expect it to turn off on its own after some drive cycles. I sure hope it does, because the LED bulb I have in the CEL spot is flipping bright.

Been working through how to wire up the defogger & rear wiper, since I eliminated those switches. After studying the wiring diagrams, I think I finally have a handle on it with the understanding that I don't care about the illumination circuit (I don't need them to light up when I have the headlights on).

The defogger is pretty simple. You just ground the dark blue/light green wire, and the instrument cluster takes care of the rest. Eventually the defogger relay turns on and powers the defogger directly, and sends 12V back to the switch on the black/white wire. So a SPST will handle the on/off, and a separate LED can handle the on/off indicator light.

The wiper is more complicated. At rest, the wiper motor needs to be grounded for the wiper park function to work. When you turn on the wipers, that ground is removed and replaced with 12V supply from fuse #6. When you want the washer, the switch puts 12V on the washer pump and also does the wiper function as described above.

Removing the ground on the wiper motor is the complicated part. It can't easily be done with any normal switch.

Relays have entered the chat.

My idea is to use a relay to remove the ground. I'm somewhat new to the world of relays, and this represents the reverse of every youtube video out there on how to wire an automotive relay. The thing to remember is that a 5 pin relay only does 2 things: (1) it connects 30 to 87a when not energized, and (2) connects 30 to 87 when it is energized. So if we put the wiper motor on 30, ground on 87a, and the 12V supply on 87, the relay will ground the wiper motor at rest, and will power the wiper motor when energized.

Add in a momentary DPDT to handle the physical switching, and I'm pretty sure I've solved the problem. It's unconventional to put the supply on 87 and load on 30, but I see no reason why it won't work. I mean, it's a relay not a diode (unless there's a diode in there!). It's also probably unconventional to use the supply to also trigger the relay (dotted blue wire below) but I don't see any reason this won't work either.

hear said:

CEL is still on with a stored P0743 code, but I expect it to turn off on its own after some drive cycles. I sure hope it does, because the LED bulb I have in the CEL spot is flipping bright.

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CEL was off and all codes were gone when I got in the Jeep Sunday morning to drive to OK, has stayed off ever since. Also, all the sensors show ready, so I'm 100% good to go. I'm low-key sad that I'm emissions exempt as of Jan 1, because I would pass! Didn't even need to put in the new O2 sensors I bought.

After some discussions with another member, I decided that it's probably best to replicate the washer switch as closely as possible, which means that I need a DPDT that latches at one layer, and then is momentary at the next layer, or an (ON)-ON-OFF DPDT. Turns out this is not the easiest switch in the world to find, and Amazon doesn't carry it. I ended up finding it on Mouser, and it's about $17 + $8 s/h. This project just got expensive, considering I pretty much never use the rear wiper or defogger. I forget how spoiled I am by Amazon Prime. Anyway, it will be here tomorrow.

https://www.mouser.com/ProductDetail/690-6GG5B-78
The new wiring will look like this:



I also went with a momentary push button "angel eye" switch for the defogger. It was one of the few options with an integrated LED that wasn't powered by the same source that was being switched. The factory defogger switch triggers a ground and the LED is powered by a signal from the defogger relay, so my new wiring will be identical to that.

Had a super busy week at work (for a change) and I have to build a basketball hoop for my kid, so I'm anxious to actually put all this theoretical circuitry to the test. I normally prioritize Jeep over nearly everything, but this week I've been forced to do a prioritization inversion.

machoheadgames said:

I missed where you wrote up the relay diagram but looking at it, I see no reason why it won't work perfectly. You can run 30 as the output to accessories perfectly fine unless it's a diode relay, which do exist but are not so common. Your little trick would flip the motor between power and ground just fine. I run relays backwards all the time depending on what I need them to do.

The factory builds the ground source straight into the switch so when the switch is off the motor automatically gets ground. Damn near impossible to find a switch that does that without shorting something.

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Yeah, I basically worked through it a bunch in my head and realized that I was overthinking it. Again, all a relay does is connect 30 to 87a while the 85/86 is open, and breaks the 30/87a in favor of 30/87 when the 85/86 circuit is closed. I'm sure they can do all manner of other tricky things, but for a Bosch style automotive relay that's all there is. A month ago I was intimidated by them, now I'm finding clever ways to make them control circuits.

I have a B.S. in Physics, but I dropped Circuits and Electronics was all about semiconductor doping and how to make an op amp control a 7 segment display...not super handy in anything I spend any time doing. Although the time I've spent on wiring this Jeep has probably taught me more about DC circuitry than the class ever would have.

Finally had a free moment to get into the garage to “finish up” my wiring project. Before I start cutting wires I wanted to validate that my modifications would work. Only had time to test the new defogger switch, but it was a rousing success.

Momentary switch turned on the defogger, LED lit up, and turned off right at 10 mins later. Also pressing it again turns it off, which I was HOPING would happen. The logic for all this is in a microprocessor on the instrument cluster, so I had to make an educated guess that re-grounding the relay would turn it off.

You can’t imagine my joy when the LED turned off on its own. I don’t know that I ever used the defogger before, so it could’ve not worked for a number of reasons.

Also debated about which switch to use. I have LED tip toggles wherever possible, but seems like every one of those uses the power that is being switched to run the LED. The switch I went with has 5 leads (NO & NC) and powers the LED independently. Also comes with a pigtail plug so it’s easy to tear all this apart later.

hear said:

After some discussions with another member, I decided that it's probably best to replicate the washer switch as closely as possible, which means that I need a DPDT that latches at one layer, and then is momentary at the next layer, or an (ON)-ON-OFF DPDT. Turns out this is not the easiest switch in the world to find, and Amazon doesn't carry it. I ended up finding it on Mouser, and it's about $17 + $8 s/h. This project just got expensive, considering I pretty much never use the rear wiper or defogger. I forget how spoiled I am by Amazon Prime. Anyway, it will be here tomorrow.

Click to expand...

Mouser was awesome, for a brief moment. That $8 shipping fee actually got me the part the next day. Unfortunately it was not even close to the right part. It took them 6 days to get it straightened out (I had to provide visual evidence that it was the wrong part), and then finally shipped the correct part. But the tracking showed it was on the slow boat so I'd lose another weekend. I complained about that.....they refunded my shipping cost (didn't ask for that, they should've just shipped it the same method as what I paid for) and then the part showed up 3 days early. Whatever. I'm sure they're great if you're buying 1000 of something. Oh well. In the end they made it right, debatably even better than right. So, low key recommend?

Haven't had much to do on the jeep, everything's been running great....till last week. Drove fine on Friday, then Saturday it decided to sort of idle rough in drive & reverse in the driveway, but it wasn't major and was hard to quantify. While driving, it was holding on to first for a LONG time....like it wouldn't shift till close to 5k RPM, and then would go directly to 3rd. There's a whole thread about it on the main forum.

Cut to the chase: found kick down band friction material in large chunks in the trans pan. ATF was pretty darn clean, no burnt smell at all. The fluid is a year old but less than 5k miles...but a lot of offroad hours. And I drove it less than 10 miles since it started acting up, hopefully that means I didn't incur any serious damage.

Re-man 32RH is about $2k + a $1500 core charge, plus shipping both ways.
Used units are between $1300 & $1600 shipped for a unit with ~100k miles on it, and a 90 day warranty
Local show ballpark quote to rebuild was $2500-$3000.
Rebuild kit with some upgraded parts came in at around $400, plus a TC if I decide to get a new one.

I don't see me saving between $600 and $1000 to get a used unit with a junk warranty as being a smart play here, so it's either rebuild myself or buy the reman unit. Having watched several videos and read the FSM several times, feels like it's worth the gamble to attempt this myself. Worst case scenario is I blow up my trans, but it doesn't make the core worth any less so feels like the right gamble.

I hope to make a video walkthrough of this, but I'll have to rope a kid into being the camera man probably.