Extended Idle 97-01 Install

[compcrasher86]

Heres a nice little tutorial for those with 98's, I just did mine:

I decided not to make the splice right at the ECU just because it was kinda far from my switch, I wanted the shortest wire run, and I wanted it to be protected from the elements. So I pulled off the connector and confirmed pin A12 on the black connector. Then farther up the wiring harness, near the master brake cylinder area I picked through the harness in the split loom and found the "solid grey wire" everybody seemed to have. So I then shaved a bit of the insulation off with a razor knife and using a multimeter, confirmed it had continuity with pin A12. Be careful, there are plenty of grey wires in there with stripes, you don't want those!

(Just a little side note, I did trace the grey wire till it ended, and it ends in a wiring harness connector over by the distributor cap. There is a little plastic blocker over the other side of the connector that essentially caps the wire off. Police packages probably had a different wiring harness that had the grey wire on the other side of that connector and brought it into the dash. I chose over by the master cylinder because thats the closest accessible area to get through the firewall)

Then I cut the wire, and soldered my new extension wire in (I kept with grey just for color coding purposes), slipped a piece of heatshrink over, and re soldered the original wires back together. Slipped the heatshrink over and used a heatgun to seal it

Then I ran it along an adjacent wiring harness and through the rubber boot through the firewall by poking a hole and threading it through with a coathanger. This was by far the most time consuming part because the rubber boot was a PITA to pierce. I then popped the wire into the split loom and taped wherever it was loose. This shows where the wire crosses from the ECU harness over to the one that goes into the rubber boot in the firewall

For my ground I popped open the connector for the factory fogs and soldered a thin black wire to the gnd for the fog switch, popped the connector back together and voila

I cut out a piece of the factory blank and am using this temporary switch until I can bring myself to buy the factory one

Overall the job is invisible because the wires are well hidden and bound up, the connections were made well and waterproofed under the hood, and my extended idle switch works GREAT. Bumps it up to 1100/1200 rpm for me. I don't know how often I'll be using this but when I have to do a jump start or in hot situations, this switch will DEFINATELY be worth it

 

[Blaine B.]

Did anybody figure anything out for OBD1 XJ's and the extended idle? Are the PCM's different for the civilian XJ's and Police XJ's for OBD1? My extended idle in my 95 is still not working....

 

[dagr8tim]

If you have a lighted switch with "normal" instructions it's kind of backwards......you have to switch around negative/positive on the switch in order for it to light when your high-idle is on, and not backwards.....I have a diagram somewhere.

Just so I'm understanding it, on my Civi 97, there is no ext idle switch or the wiring behind the switch. Can I just tap the gray wire (pin 12) and run the wire to a 2 prong toggle. Then ground the other prong?

I'm assuming that electricity flows from pin 12 to ground. I'm just asking because I want the indicator light on my aftermarket switch to light up.

 

[Blaine B.]

A 2 prong toggle would be no problem. Yes, one side would be tapped to the grey wire and the other side would go to ground. Since it is not lighted there is no need for +12volts for the bulb.

 

[dagr8tim]

A 2 prong toggle would be no problem. Yes, one side would be tapped to the grey wire and the other side would go to ground. Since it is not lighted there is no need for +12volts for the bulb.

Cool, if I wanted a light would I need an extra wire, or would the 12 volts to ground from the gray wire be enough to power an indicator light?

 

[Blaine B.]

The ground for the bulb would not come from the grey wire. It would come from the wire that goes to ground on the switch itself.

The other 3rd terminal would need to receive +12 volts, probably also best accomplished by tying into one of the +12 volt leads for one of the other switches. Just to make sure it is switched and not a constant +12 volt source. IE not hot when the vehicle is off.

 

[dagr8tim]

The ground for the bulb would not come from the grey wire. It would come from the wire that goes to ground on the switch itself.

The other 3rd terminal would need to receive +12 volts, probably also best accomplished by tying into one of the +12 volt leads for one of the other switches. Just to make sure it is switched and not a constant +12 volt source. IE not hot when the vehicle is off.

You can get 2 terminal switches with an indicator light. You are saying that the power from the ECU that is going to ground could not power the indicator light as it pass through the switch when it is activated?

No bigs, I'm sure I can snag the power from my fog light switch, or even use the fog light switch (as I don't have fogs) for the ext idle switch. Thanks for all the help.

 

[smccollamjr]

I'm not up on LEDs, but incandescent light bulbs don't care which way electricity is flowing. Which leads me to believe you could connect 12v to the ground lug on the switch, ground one of the switched lugs, and connect the gray wire to the other. I've got a couple switches with LEDs lying around. I'll try connecting them backwards tomorrow and see what happens.

 

[fyrfytr1717]

Did anybody figure anything out for OBD1 XJ's and the extended idle? Are the PCM's different for the civilian XJ's and Police XJ's for OBD1? My extended idle in my 95 is still not working....

Wow Blaine, sorry to hear a solution for OBD1 still hasn't come around for you.

 

[fyrfytr1717]

You can get 2 terminal switches with an indicator light. You are saying that the power from the ECU that is going to ground could not power the indicator light as it pass through the switch when it is activated?

No bigs, I'm sure I can snag the power from my fog light switch, or even use the fog light switch (as I don't have fogs) for the ext idle switch. Thanks for all the help.

I'm not up on LEDs, but incandescent light bulbs don't care which way electricity is flowing. Which leads me to believe you could connect 12v to the ground lug on the switch, ground one of the switched lugs, and connect the gray wire to the other. I've got a couple switches with LEDs lying around. I'll try connecting them backwards tomorrow and see what happens.

Curious to see if this will work. Never really thought of the ECU as being a +12V source. I thought you were just supplying a ground "signal" to the ECU to activate the extended idle. However, I guess if you're grounding the circuit that means electrons are flowing through it. :dunno:

dagr8tim, keep in mind that if you do use the fog light circuit for your power source, it is only hot when your parking lights (or headlights) are on and your high beams are off. I'd tap into the dark blue w/ white tracer for an ignition switched 12V+ source if you end up needing one. Refer back to post #149 for more info.

 

[Blaine B.]

No, the ECU is not giving ground, you are feeding ground TO the ECU.

And then ground alone will not power a bulb, you will also need a +12volts source to light the indicator.

 

[fyrfytr1717]

Re: Here it is, the answers you've been looking for!

Heres a nice little tutorial for those with 98's, I just did mine:

I decided not to make the splice right at the ECU just because it was kinda far from my switch, I wanted the shortest wire run, and I wanted it to be protected from the elements. So I pulled off the connector and confirmed pin A12 on the black connector. Then farther up the wiring harness, near the master brake cylinder area I picked through the harness in the split loom and found the "solid grey wire" everybody seemed to have. So I then shaved a bit of the insulation off with a razor knife and using a multimeter, confirmed it had continuity with pin A12. Be careful, there are plenty of grey wires in there with stripes, you don't want those!

(Just a little side note, I did trace the grey wire till it ended, and it ends in a wiring harness connector over by the distributor cap. There is a little plastic blocker over the other side of the connector that essentially caps the wire off. Police packages probably had a different wiring harness that had the grey wire on the other side of that connector and brought it into the dash. I chose over by the master cylinder because thats the closest accessible area to get through the firewall)

2. The Idle Actuator wire that gets connected to Pin A12 on the PCM has been pretty well covered. I did however follow the wiring schematic in hopes of tracking down the closest possible spot to tap into the existing (Solid Grey) wire. Turns out that it doesn't get much better than right next to the PCM. Unless you have the Police Package (in which case you probably don't need to do this mod) the Solid Grey wire runs from Pin A12 on the PCM to Pin 11 on Connector C107 which you will find right next to the transmission dipstick. That's it, it stops there. This connector is actually further away from the driver's side firewall hole than the PCM is. I guess you could split the loom, find the Solid Grey wire, and splice into it right next to the firewall hole if you really wanted to.

This brings me to my next point. As this Solid Grey wire is not connected to anything other than A12 on the PCM, it doesn't matter whether you choose to cut or splice the Solid Grey wire to make your connection. Electrically speaking, it's the same either way.

Was curious to see if some one was going to try this. Glad it worked for you.

Then I ran it along an adjacent wiring harness and through the rubber boot through the firewall by poking a hole and threading it through with a coathanger. This was by far the most time consuming part because the rubber boot was a PITA to pierce. I then popped the wire into the split loom and taped wherever it was loose. This shows where the wire crosses from the ECU harness over to the one that goes into the rubber boot in the firewall

I installed a grommet in the circle marked with an "X" in your above picture and ran it through there. Didn't want to mess with the boot and as I've got about a dozen other wires as well as a couple of air lines running through it, my boot would have looked like swiss cheese by the time I was done.

Overall the job is invisible because the wires are well hidden and bound up, the connections were made well and waterproofed under the hood, and my extended idle switch works GREAT. Bumps it up to 1100/1200 rpm for me. I don't know how often I'll be using this but when I have to do a jump start or in hot situations, this switch will DEFINATELY be worth it

Good work on the install. I like it clean like like that.:thumbup:

I find I use mine for jump starting, winching, running my air compressor, and most often, while sitting in line at the drive through window. Shift it into neutral and your idle kicks up, back into drive and it automatically kicks down. I figure I might as well make my alternator do a little work while I'm just sitting there...

 

[dagr8tim]

I'm not up on LEDs, but incandescent light bulbs don't care which way electricity is flowing. Which leads me to believe you could connect 12v to the ground lug on the switch, ground one of the switched lugs, and connect the gray wire to the other. I've got a couple switches with LEDs lying around. I'll try connecting them backwards tomorrow and see what happens.

With moving and everything else, I'm not going to be able to mess with this until the weekend after this coming one. Let me know how it goes.

My thought is if you are grounding the wire, you are drawing off whatever voltage is coming from the ECU. So why can't you use that voltage that you are draining off to ground to power a light.

 

[scavengerj]

Thanx to all for brining this thread back up. Definitely something I am going to be doing. Never truely understood the purpose until now. Duh.

I do have one question though, if going with a higher rated alt., is this mod needed?

 

[larjerr1]

Hello,
With the help of JEEPZZ and many others. I have completed the install for the extended idle. It works great and it was not hard to install. As asked by JEEPZZ to reply on the activation light. I too could not get it to light up. I connected the ground, fused panel lamps dimmer switch signal, and the idle actuator, but did not connect fused ignition switch run. When I did connect the fused ignition switch run wire up to the correct color and number off the A/C plug. The switch did not work at all and the lights all dimmed in the car. So I cut it loose and left it unhooked. Also I did bypass C100 and C107 when running the wire from the switch to PCM C1 #12. If anyone knows how to get the light to work. I would really appreciate it.
Alex

Hey guys, just joined so i could post this, your local dealer can get the pigtail for a 97+ cherokee it's part #
68057305AA (It's about $30 online dealership)

Found it here..
http://dto.vftis.com/mopar/disclaimer.asp
You can find most all connectors there.....

Btw, thanks for the schematic above. My 1998 factory service manual has the same drawing but with pins 1 and 4 reversed. Lucky I just blew a fuse and not the computer. It idled up but instantly blew the fan motor fuse and then when I cut off the switch it stayed idled high till i cut the jeep off and restarted.
Also there are numbers near the switch pins, and on the connector, but they mate up backwards. 1 to 4, 4 to 1. According to how the other switches are wired the numbers on the connector are the numbers to use. Anyone ever had to remove pins from the connector? I hate to do more splices...
Also it sure would be helpful if someone took a pic of the pigtail showing correct wire placement. I'm not positive still which is right..don't want to fry it for real next try....

 

[fyrfytr1717]

Re: Here it is, the answers you've been looking for!

Nice find on the pigtails! Here's the pin out information for your extended idle switch. Refer back to post #149 in this thread for full details.

3. Extended Idle Switch wiring is as follows (per the FSM):
Pin #1 - Ground (Black on the OEM Ext Idle pigtail)
Pin #2 - Idle Actuator (Grey on the OEM Ext Idle pigtail)
Pin #3 - Fused Ignition Switch Output (RUN) (Dark Blue w/ White stripe on the OEM Ext Idle Pigtail)
Pin #4 - Fused Panel Lamps Dimmer Switch Signal (Orange on the OEM Ext Idle Pigtail)

Unless you managed to score a pigtail from a Police Package XJ, your pigtail will not match up. I chose to use the Defrost pigtail since the #1 & #4 (Black & Orange) leads are the same as the original pigtail. Here's the easiest way to wire it all up:

Connect Ext Idle Switch Pin #1 to Fog Lamp Switch Pin #4 (Black)
Connect Ext Idle Switch Pin #2 to your wire leading to A12 on the PCM
Connect Ext Idle Switch Pin #3 to A/C Heater Control Pin #2 (Dark Blue / White stripe)
Connect Ext Idle Switch Pin #4 to Fog Lamp Switch Pin #1 (Orange)

So why do you tie into A/C Heater Control Pin #2 instead of the hot lead on the Fog Lamp Switch? Because if you use the Fog Lamp Switch as your power source, your Ext Idle indicator light will only come on when your Fog Lights are allowed to come on (i.e. headlights on, high beams off). If you use the Fog Light Switch lead, your Ext Idle indicator light won't come on when your headlights are off and it will turn off anytime you turn on your high beams. Best reasons of all though... the A/C Heater Control wire is close enough that you don't need to extend your Ext Idle pigtail and it is the power source used when Ext Idle is a factory option as shown in the diagram below.

You're probably saying, great, now I've got to figure out where the heck A/C Heater Control Pin #2 is too... It actually couldn't be easier. Directly above your new Ext Idle switch is the A/C Heater control knob (Hot/Cold). On the back of the knob you will find a plug with three wires. Follow the wires down and you will see they run right past the back of the Ext Idle Switch. The middle one is the Dark Blue with White stripe that you are looking for. Splice into it and connect it to Ext Idle Switch Pin #3. Easy as pie.

 

[Blaine B.]

Has anybody figured out why this will not work with OBD 1 non-police setup? Grounding the proper pin does absoultely nothing.....no change in idle RPM, no nothing. Never see any OBD1 XJ's in the junkyard which were ex-Police so scoring the Police PCM would be pretty much as rare as it gets. I thought it might be possible with the "civilian" PCM too, as it is with the OBD2 96-01's........

 

[mrtosh]

Quick question. How exactly does the enxtended idle switch work? Does it affect the TPS or the IAC causing them to open more?

 

[srmitchell]

I think it would have something to do with the cruise servo?

 

[kastein]

mrtosh, can't affect the TPS as that's a sensor not an actuator. It would have to open the IAC further or use the cruise servo to open the throttle further, yes. Not sure which but that's easy enough to answer... anyone have an XJ with no cruise, but with extended idle? Or can anyone with an XJ with cruise+extended idle unplug their cruise servo and try using the extended idle switch as a test?