Extended Idle Switch

I will start a thread here for some wishing to do this. I am wanting to incorporate the Extended Idle Switch Assembly from a Police Package XJ, to one not so equipped. Here is what I know(pics will come once I get them loaded onto my computer at home). Here is my current project--1994 XJ Sport, 4.0, 231, AW4. Donation vehicle: 1995 XJ 4.0, 242, AW4. I am going to begin with the disassembly of the 1995 for transplant into my 1994. There is one screw holding the unit in the dash, and then the assembly can come out as a whole. Once out, then it is tracing the wiring back to its origins for the transplant. The Extended Idle Switch has three wires on the back side(For all purposes the colors being exampled here could differ from year to year): Red/white stripe, purple, and a ground wire, that ties into the ground group in the main dash harness. The Red with white stripe goes to the 3amp accessory fuse in the block under the dash. The purple wire goes into the grommeted unit that goes into the engine compartment. This wire goes into the ECM on the post topside, row, first to the right of the screw that holds the connector in place(again pictures will be posted once I get them up). I haven't figgered out what that post does on the ECM, but if someone here could enlighten me on the "coding" or purpose, that would be outstanding. Now is the tricky part, how to install this, when my XJ wasn't setup for it, or so far, I haven't found a harness identical to the unit this was pulled out of. When I deinstalled the wiring from the 1995, I made sure to pull out the connectors from both the fuseblock, and the firewall grommet, it helps to have a jewelers flathead screwdriver for this part. If my memory serves me right, the ECM already has the wire for purple wire to hook to. In order to make it look somewhat "factory", I have to employ the use of the connectors for the reinstall in my 1994. I also then have to tie the existing backlighting wires into their prospective locations as well. Once I remove my existing rear defrost switch panel, I will know if DC left the provision for this wiring into the '94s dash and firewall harnesses. Input here is welcomed, and further postings will follow, once I have my other vehicle back so I can begin the reinstall procedure. Again, I will post pics within the next 24hrs.

For the 94 and 95 it should be pin 10 on the pcm plug which is extended idle. Simply ground this pin and the idle will raise to 1000 when in park or neutral.

Except your 94 probably won't have the female metal insert on the plug. The pin will be there on the PCM, but not on the plug...

My 95 is the same way. I'll have to find a female insert for the plug so I can wire up my extended idle switch.

Once I post pictures, it will all make sense. I am trying to write it down so that I can remember which wires go where. I just did the deinstall and forgot to get pics of that, but I will post of the switch and its parts. I will also do a continuity test of the switch as well, to prove or disprove the grounding of pins. I think the pin on the ECM, actually needs power to be able to idle up in Neutral or Park. Once I test the theory, I will also post up the results and procedures. Pics help here, sorry for their lack thereof(once they are loaded though lookout). For the plug, just tap into the wire harness. I may do that if it takes me too long to get the wires right in the main harness. That is why I traced everything back to where it connected, then traced the pins on the ECM, it just isn't marked on the ECM which one is which, but the 95 had the purple wire running all the way from the switch to the ECM, and it stayed purple the whole time. Even the FSM doesn't really go into great detail about this item either, which sucks when it comes to doing this modification(even though it is technically stock). I have a lightbar and several FD radios and I want it to be able to pump up the amperage some.

My only ? would be are the perameters for that option allready programmed into all PCM's or would it have to be spec'ed out w/that option.

Nope, you ground the pin to activate the higher idle.

The PCM should be able to do it. That's why the pin is there in the PCM. But the plugs don't always have the female terminal. They have the hole, but no metal insert nor wire....so you have to add that.

What kind of lightbar? Here's my setup.

Those perameters are already in the ECM, so it will work on any XJ to my knowledge. Blain, go to www.midwestjeepthing.com and look up my name-ihscoutlover and you can see a profile of my XJ, I cannot seem to figger out how to post the pictures on here. I have an MX7000, 6 Strobe Whelen setup, front and rear wig wags, as well as two 110watt Motorola Spectra radios. I also have Whelen's electric Air Horn/PA unit. What is your thought on a new alternator? Mines putting out only 30 amps, rated for 90? Then why the other wires, it should have just two, and it has three, one of which goes to the 3amp fuse in the fuse block? Also where did the spotlights hook into the harness? I got the one off this XJ as well and I am gonna put it in mine.

Jeff

ihscoutlover said:

Those perameters are already in the ECM, so it will work on any XJ to my knowledge. Blain, go to www.midwestjeepthing.com and look up my name-ihscoutlover and you can see a profile of my XJ, I cannot seem to figger out how to post the pictures on here. I have an MX7000, 6 Strobe Whelen setup, front and rear wig wags, as well as two 110watt Motorola Spectra radios. I also have Whelen's electric Air Horn/PA unit. What is your thought on a new alternator? Mines putting out only 30 amps, rated for 90? Then why the other wires, it should have just two, and it has three, one of which goes to the 3amp fuse in the fuse block? Also where did the spotlights hook into the harness? I got the one off this XJ as well and I am gonna put it in mine.

Jeff

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x2.? If the pin just needs to be grounded then why the other wire going to the fuse block?

there is a light in the circuit to tell you it's on

the switch has two black wires, one to ground the other supplies ground for the lamp. The violet turns to orange at firewall connector goes to PCM. The white w/ red stripe goes to switched 12Volts. colors may very from year to year, theses are for a 95.

I followed the wires all the way through the firewall. It stays purple the whole time. It has one junction, and that is at the firewall grommet. If it is the orange wire on yours, then perhaps show me a picture, as I followed everything for about 45 minutes, and that is what I found. The wiring diagrams in the Haynes and Chiltons books are wrong, and as for the FSM, I didn't find a very descriptive color prior to the deinstall.

I was looking at the diagram on Alldata for a 95 w/ police pachage

Post the link, I will take a look, but as far as I traced, and it took a lot of time to follow the wires, it stayed purple all the way to the ECM.

I cannot post it, as have taken sheet from peep's, just like your not suppose to post stuff from the FSM's. Copywrite issues. The diagram says the wire changes colors at connector c108. But go with what you got, it wouldn't be the first time I found a wiring diagragm yo be wrong.

ihscoutlover said:

Post the link, I will take a look, but as far as I traced, and it took a lot of time to follow the wires, it stayed purple all the way to the ECM.

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PM sent

I'd like to figure out how to do this to my 87' RENIX.

sorry, can't be done on a renix. one of those lockable hand throtles would work though

hey allright another midwest jeep thing member, whooo!!!

What's an extended idle switch do?

megabyte5689 said:

What's an extended idle switch do?

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the switch raises the idle to allow the jeep to idle for long periods of time

I don't see why this would have been in a police package jeep, you can practically leave the jeep idling all day provided you have enough gas.