Thanks to @Drizit for suggesting bring this article over. It was originally found on Jeep Kings, a Canadian Jeep forum.
Okay, so for a while I have been thinking this over in my head how I was going to create some type of high idle switch. I originally thought of using vacuum but couldn't come up with a good way to do it. Then I thought of using a small solenoid at the throttle. Then I thought how about using the cruise control system to do this. I started searching around the internet a way to do this with SPDT relays. You can do this on any vehicle that uses the same servo as my ZJ (93) which apparently is alot. This will let you keep your cruise control working like normal when the switches are not in use.
Parts List:
You will also need this wiring diagram. Courtesy of mallcrawlin. (ZJ's kickass)
Once you turn the power on, the led lights up and the relays energize. To increase idle you tap the momentary switch up and to decrease you tap down.
This is part one I will finish it within the next few days when I do the in truck wiring for the switches.
The first thing I did was make my bracket. Then I found a spot to mount it at the highest point I could find that was pretty protected from water. I decided on my passenger side fender at the front beside the battery. It was about the only open space I could find to mount it out of the way, that wasn't to low or I knew it was going to get wet. It was also close enough to the servo that I wouldnt have to run a ton of wiring.
Bracket made with relays attached
The spot where I chose to mount the bracket and relays to. Test fitting it.
I then took the relays out and proceeded to start wiring all of the wiring that could be done outside of the truck on the work bench. (Relay to Relay, Ground wires, etc). I then test fitted it again to make sure the wires weren't going to hang to low.
The four wires joined together with the tape on the end are to be wired to the switch. You can also see one of the relays connect to each other. The other four are ground wires.
Next locate the plug on the servo and unplug it. The black is ground. These are the wires you will need to tap into so you can make this work. Cut the three wires leave enough on both ends that you will be able to splice wiring into both. Wire as diagram provided shows.
The plug unplugged with the ground and 3 other wires seperated.
Spliced together. Soldered, then shrink wrapped all connections, then I taped the wires coming from the plug at the servo together and the wires from the loom going to relays together.
Plugged back into the servo.
All of the relays connected, grounded. Relays connected to servo. (Note I also used the factory battery ground location as my ground. Since I had to undo the bolt I decided I would also change my battery ground cable since it looked like it was the original one from 93.)
At this point I reinstalled my battery as there is only 3 wires that I still have to connect. I will have to remove the battery again when I wire the switch to connect the last 3 female disconnects to the relays. But that is part two in a few days.
Okay, so for a while I have been thinking this over in my head how I was going to create some type of high idle switch. I originally thought of using vacuum but couldn't come up with a good way to do it. Then I thought of using a small solenoid at the throttle. Then I thought how about using the cruise control system to do this. I started searching around the internet a way to do this with SPDT relays. You can do this on any vehicle that uses the same servo as my ZJ (93) which apparently is alot. This will let you keep your cruise control working like normal when the switches are not in use.
Parts List:
- 4 SPDT relays
- 1 on/off switch
- 1 inline fuse
- 1 indicator light
- 1 2 way switch
- Wire (I used 12g but thats just because i had it laying around in bulk rolls, the factory wiring is 18g, Which when wiring at the servo will make your life way easier if you user similar gauge wire. I used two different colors to easily identify the ones from the servo and the relays, grounds from one another.)
- .250 female disconnects
- Self tapping screws
- A piece of sheet steel to make a bracket out of
- Soldering gun, Solder
- Electrical tape
- Wire strippers
You will also need this wiring diagram. Courtesy of mallcrawlin. (ZJ's kickass)
Once you turn the power on, the led lights up and the relays energize. To increase idle you tap the momentary switch up and to decrease you tap down.
This is part one I will finish it within the next few days when I do the in truck wiring for the switches.
The first thing I did was make my bracket. Then I found a spot to mount it at the highest point I could find that was pretty protected from water. I decided on my passenger side fender at the front beside the battery. It was about the only open space I could find to mount it out of the way, that wasn't to low or I knew it was going to get wet. It was also close enough to the servo that I wouldnt have to run a ton of wiring.
Bracket made with relays attached
The spot where I chose to mount the bracket and relays to. Test fitting it.
I then took the relays out and proceeded to start wiring all of the wiring that could be done outside of the truck on the work bench. (Relay to Relay, Ground wires, etc). I then test fitted it again to make sure the wires weren't going to hang to low.
The four wires joined together with the tape on the end are to be wired to the switch. You can also see one of the relays connect to each other. The other four are ground wires.
Next locate the plug on the servo and unplug it. The black is ground. These are the wires you will need to tap into so you can make this work. Cut the three wires leave enough on both ends that you will be able to splice wiring into both. Wire as diagram provided shows.
The plug unplugged with the ground and 3 other wires seperated.
Spliced together. Soldered, then shrink wrapped all connections, then I taped the wires coming from the plug at the servo together and the wires from the loom going to relays together.
Plugged back into the servo.
All of the relays connected, grounded. Relays connected to servo. (Note I also used the factory battery ground location as my ground. Since I had to undo the bolt I decided I would also change my battery ground cable since it looked like it was the original one from 93.)
At this point I reinstalled my battery as there is only 3 wires that I still have to connect. I will have to remove the battery again when I wire the switch to connect the last 3 female disconnects to the relays. But that is part two in a few days.
