What do I need to install rear defrost switch on my 1999 TJ?

[Jmr17320]

So I am adding a hardtop with rear fogger to a 1999 Jeep that had a hardtop but no defogger?

I added the relay under the hood, I have added the defogger switch to existing plug. BUT when I go to the fuse box behind the glove box to ad the fuse for rear defogger, it is an empty slot.

what do I need to do to get this working?

 

[qslim]

Fuse #17 should be the one behind the glovebox. If the terminals are missing then it sounds like that part of the harness wasn't wired from the factory & you may have to either wire it or piggyback a wire with an inline fuse.

Do you already have a 40a fuse in #15 under the hood in the PDC? Makes me wonder what else is missing.

 

[Jmr17320]

Slow day here at work, so I have been reading tons of threads on this topic.

I failed to mention, I have a V8 swap and I am not using the OE instrument cluster. Is the OE cluster where the timer is located?

relay - swapped out with starter, no change.

Glove box fuses - all fuses are in and
checked

under hood - all fuses in and checked

 

[qslim]

Slow day here at work, so I have been reading tons of threads on this topic.

I failed to mention, I have a V8 swap and I am not using the OE instrument cluster. Is the OE cluster where the timer is located?

relay - swapped out with starter, no change.

Glove box fuses - all fuses are in and
checked

under hood - all fuses in and checked

I couldn't tell you why it goes through the IC, but yeah it might be the timing function. If you aren't using a factory IC then that's another variable for you. If you're handy with a meter looks like you could check for ground on terminal D6 of your defogger relay with the switch in the on position.

So are the terminals missing behind the glovebox in slot #17?

 

[Jmr17320]

Can you explain how to check that terminal D6?

slot 17, has a fuse

I was thinking slot 16 was for rear defogger but apparently that is for rear fog lights?

 

[qslim]

Oh ok, that makes more sense.

So for checking to see if your aftermarket IC is the problem, you can check the ground side of the control half of the relay to ground. That circuit goes from terminal 6 down through your IC, up through your switch & lamps inside, & down to a ground point. Just pull the relay, set your meter to OHMs, put one probe in terminal 6 of the relay cavity & the other probe on the negative battery terminal. You should get a single-digit reading, if you don't I'd suspect that aftermarket IC.

 

[Jmr17320]

Seeing how I have auto meter gauges, I know the timer has been deleted from the system.

I wonder if I made a jumper between port 3 and port 4, in connector C1, if this would give me what I need. I know without a timer, I’d have to manually turn it off but that is fine

 

[qslim]

Yeah that's what I would do.

 

[Jmr17320]

Will give her a try, will report back when I know more

 

[qslim]

Will give her a try, will report back when I know more

Yeah let us know if that does the trick.

Out of curiosity why do you have an aftermarket IC? Is part of the V8 swap thing?

 

[Jmr17320]

Not an after market instrument cluster, I removed the OE cluster as all my gauges work off GM sensors. So I had to install auto meter gauges in a custom TJ gauge panel

 

[Jmr17320]

Here this is it

 

[Jmr17320]

So I made a jumper between port 3 and port 4, in connector C1. The switch when HELD IN THE ON position, works! Oh yeah! But because the switch is a momentary switch (activated when pressed, vs. on until you turn it off) it turns off as soon as I move my finger off the switch. Thinking about getting an aftermarket switch for say a fog light that is on/off. This will get me what I need.
At least I am in the path to a solution

 

[qslim]

So I made a jumper between port 3 and port 4, in connector C1. The switch when HELD IN THE ON position, works! Oh yeah! But because the switch is a momentary switch (activated when pressed, vs. on until you turn it off) it turns off as soon as I move my finger off the switch. Thinking about getting an aftermarket switch for say a fog light that is on/off. This will get me what I need.
At least I am in the path to a solution

View attachment 222922

Nice! You just gonna get behind that connector & splice those wires?

 

[Jmr17320]

I decided to tear apart the switch. Inside is a spring and small plunger. Careful if you do this as there is a small spring and copper u at the back side that you don’t want to lose.

once I removed the small spring and plunger, the switch works like a regular toggle switch. Just reinstalled switch into factory wiring. Done!

 

[Duner]

So I made a jumper between port 3 and port 4, in connector C1. The switch when HELD IN THE ON position, works! Oh yeah! But because the switch is a momentary switch (activated when pressed, vs. on until you turn it off) it turns off as soon as I move my finger off the switch. Thinking about getting an aftermarket switch for say a fog light that is on/off. This will get me what I need.
At least I am in the path to a solution

View attachment 222922

If you aren’t using the timing feature in the IC why do you even need to jump those two ports? Could you just run a straight wire from the relay to the switch as the previous comment mentioned?

I’m wiring in my own hard top defroster so I’m jumping the same hurdles

 

[davedjstierle]

Slow day here at work, so I have been reading tons of threads on this topic.

I failed to mention, I have a V8 swap and I am not using the OE instrument cluster. Is the OE cluster where the timer is located?

relay - swapped out with starter, no change.

Glove box fuses - all fuses are in and
checked

under hood - all fuses in and checked

This thread looks old. I'm trying to do my TJ I put a hard top on. Yes , I think the timer is part of the cluster. Christ I spent a day to figure out what was wrong with the 4x4 light . Hard wired, not on the can. any help you can throw my way would be great. I just found the switches and would like to get it going. Thanks!

 

[davedjstierle]

If you aren’t using the timing feature in the IC why do you even need to jump those two ports? Could you just run a straight wire from the relay to the switch as the previous comment mentioned?

I’m wiring in my own hard top defroster so I’m jumping the same hurdles

I know this is old, any help? How about the wiper washer?

 

[hear]

the cluster has a timer circuit, but what happens is when you press the momentary switch, it momentarily grounds the circuit which starts the timer and holds the relay closed.

The wiper circuit is also complicated because you have to park the arm at the end of the cycle, and also the fact that the switch is a toggle+momentary. Toggle for wiper, momentary for washer. I replaced both switches when I replaced my switch panel…I’ve got a diy wiring diagram posted in a thread somewhere, but I did use the factory cluster.

Have you looked at the wiring diagrams in the FSM?

 

[Duner]

I know this is old, any help? How about the wiper washer?

I was able to successfully add my own wiring for rear defrost and rear wiper. I created a how to thread for the defrost, looks like I didn’t get to uploading the wiper portion. The wiper is simple, pretty much have a 12V hot always to it, this is for the park position I believe. Then there’s a wire for the wiper motor, and the second momentary position is for the motor + wiper fluid, here it is below:

How-to rear defrost