Excessive wiring under dash
CF Veteran
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
Thread Starter
Seasoned Member
Joined: Oct 2013
Posts: 376
Likes: 5
From: Idaho
Year: 1991
Model: Cherokee
Engine: 4.0 Liter
Yep, indeed!
What you have there is the in-car transceiver for an old flip-phone. It's analog & TDMA, and neither technology is in use any more. It's a paperweight. Not even a museum piece. Worthless.
Basically, you installed this unit in the car permanently, with an external antenna. It had a transceiver (that's what you're seeing in there) and a cradle where your flip phone could be plugged in. Optionally, you might have had a hands-free setup, which would have included a speaker (about a 2 1/2 inch by 4 inch box) and a microphone.
This setup enabled the hand-held phone to be boosted to the full power of an installed phone (3 watts vs. .6 watts), and also gave the advantage of an external antenna.
This was important back in the day when networks were optimized for installed phones.
The connector on the end has two cables coming out of it. One goes to power (should have power, ground, ignition sense, and horn alert), and one goes to the cradle for the phone.
There should also be a coaxial cable coming out of it. Motorola insisted on using a crappy mini-UHF connector, while everybody else used the far superior TNC type.
There! More than you ever wanted to know about it!
The bottom line is this: Feel free to trace the wires, disconnect them, and cut them out.
How do I know this?
I stopped counting when I passed the 1,000 mark for phones installed. I installed cellphones in everything from junkers that didn't even run (seriously!), to multi-million dollar yachts.
I even installed a few in Cherokees!
What you have there is the in-car transceiver for an old flip-phone. It's analog & TDMA, and neither technology is in use any more. It's a paperweight. Not even a museum piece. Worthless.
Basically, you installed this unit in the car permanently, with an external antenna. It had a transceiver (that's what you're seeing in there) and a cradle where your flip phone could be plugged in. Optionally, you might have had a hands-free setup, which would have included a speaker (about a 2 1/2 inch by 4 inch box) and a microphone.
This setup enabled the hand-held phone to be boosted to the full power of an installed phone (3 watts vs. .6 watts), and also gave the advantage of an external antenna.
This was important back in the day when networks were optimized for installed phones.
The connector on the end has two cables coming out of it. One goes to power (should have power, ground, ignition sense, and horn alert), and one goes to the cradle for the phone.
There should also be a coaxial cable coming out of it. Motorola insisted on using a crappy mini-UHF connector, while everybody else used the far superior TNC type.
There! More than you ever wanted to know about it!

The bottom line is this: Feel free to trace the wires, disconnect them, and cut them out.
How do I know this?
I stopped counting when I passed the 1,000 mark for phones installed. I installed cellphones in everything from junkers that didn't even run (seriously!), to multi-million dollar yachts.
I even installed a few in Cherokees!

Thread Starter
Seasoned Member
Joined: Oct 2013
Posts: 376
Likes: 5
From: Idaho
Year: 1991
Model: Cherokee
Engine: 4.0 Liter
"So I guess my question is, even with all that stuff should there be this much wiring?"
You are probably better off leaving well enough alone. No reason to reinvent the wheel if you want a model "A" or a lawn tractor just go out and buy one.
Remember where that fuse is if your transmission gets funky.
You are probably better off leaving well enough alone. No reason to reinvent the wheel if you want a model "A" or a lawn tractor just go out and buy one.
Remember where that fuse is if your transmission gets funky.
Thread Starter
Seasoned Member
Joined: Oct 2013
Posts: 376
Likes: 5
From: Idaho
Year: 1991
Model: Cherokee
Engine: 4.0 Liter
So while we're talking about electrical and wiring, I'm having a problem with my blinkers. My left blinker blinks, but slowly, and then my right blinker doesn't blink, it just stays solid. Could this be because of a bad flasher?
CF Veteran




Joined: May 2012
Posts: 7,965
Likes: 964
From: Lost in the wilds of Virginia
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
Yep, but more likely, bad grounds. Check 'em, clean 'em.
Might be a combination, too.
CF Veteran




Joined: May 2012
Posts: 7,965
Likes: 964
From: Lost in the wilds of Virginia
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
Yeah, at firs the installers were mostly pros, but there got to be a lot of hacks in the business. Most of them, really. When I got out of it, there were high-school kids doing installs for twenty five bucks, if they bothered to show up. I charged $150, and did it right, plus I had insurance.
But all the dealers cared about was $25 vs. $150, so I got out.
Thread Starter
Seasoned Member
Joined: Oct 2013
Posts: 376
Likes: 5
From: Idaho
Year: 1991
Model: Cherokee
Engine: 4.0 Liter
Well I'm starting to get things worked out with the wiring.
1. Mirrors work.
2. Stereo and speakers work.
3. All except 3 windows work, the drivers side doesnt, the motor isnt bad the wires just broke off flush with the motor(any possible way of saving it?)
4. All dash and dome lights work.
Now for the bad.
1. Headlight switch broken.
2. Fog lights don't work.
3. Power seats stopped working all of a sudden.
4. Rear window wiper doesn't work.
5. Windshield wiper fluid motors don't work.
And there's some more little things. But I guess 277,358 miles will do that to a vehicle. But for $400 I got a running driving 4x4 Jeep, could I even be luckier?
Side note: Does anyone have a diagram or know how to put together a glove box lock for a '91?
1. Mirrors work.
2. Stereo and speakers work.
3. All except 3 windows work, the drivers side doesnt, the motor isnt bad the wires just broke off flush with the motor(any possible way of saving it?)
4. All dash and dome lights work.
Now for the bad.
1. Headlight switch broken.
2. Fog lights don't work.
3. Power seats stopped working all of a sudden.
4. Rear window wiper doesn't work.
5. Windshield wiper fluid motors don't work.
And there's some more little things. But I guess 277,358 miles will do that to a vehicle. But for $400 I got a running driving 4x4 Jeep, could I even be luckier?
Side note: Does anyone have a diagram or know how to put together a glove box lock for a '91?
CF Veteran




Joined: May 2012
Posts: 7,965
Likes: 964
From: Lost in the wilds of Virginia
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
That's an easy one. Replace it. And do the headlight harness upgrade, while you're at it. Even with a new switch, you're still working with 25+ year old wiring. Take a load off it and give yourself some brighter lights at the same time.
In automotive electrical, of course you always start with properly charged battery, and check your fuses. If that all checks out, it's time to put on your thinking cap and start troubleshooting.
First step, check to see if they light when you apply voltage to the bulb itself. They might just be burned out.
If they do, you need to figure out where the voltage is "getting lost", or more correctly, where the circuit is broken. In the electronics biz, we do what's called, "circuit splitting". This principle can be applied to the interior workings of electronic circuits, to automotive wiring, hydraulic equipment, and just about any other kind of problem.
The idea is to check the "far end" of the circuit first. In this case, the fog light bulbs themselves. If you give them 12v, and they don't light, replace them. This may solve the problem. If they do light, or you replace them with known good bulbs and they still don't work, you know the problem is somewhere between the bulbs and the battery. But where?
Pick a point that is functionally half way between the battery and the lights. (It's not critical that it's EXACTLY halfway, and remember we're talking functionally, not distance.) Test there to see if you get the expected results, which in your case would be 12v. If you don't, you apply 12v to the side of the circuit toward the bulbs. (We'll call this the far end of the circuit.) If the bulbs light, you know the problem is on the near end of the circuit, between your test point and the battery. So, pick a point that is halfway between your test point and the battery. Repeat as needed until you find the problem. Test, verify, split, repeat.
In this case of your fog lights, my first halfway test point would probably be the switch. Is it getting juice, and if so, is it putting OUT juice?
Then go from there.
Wiring under the seats has a tendency to get corrosion in connectors. Once you've checked the fuses (of course), look for that. If they are good, see the circuit splitting ideas above.
Circuit splitting time!
One more point - USE A TEST LIGHT. Meters are great, and should definitely be in your tool box, but sometimes, they can lie to you. If there is corrosion in a connection upstream (toward the battery), the meter may show 12v, but when you put a load on it, that voltage may drop to near zero.
This is because the corrosion can (usually, WILL) create a high resistance. This resistance will choke the flow of current down to the point where a device (fan motor, light bulb, whatever) will not be able to function. BUT, since a meter doesn't draw any appreciable amount of current, it will still show the correct voltage.
So, where corrosion may be a factor, use a test light.
Man, that is one SWEET deal! I see them going for seven or eight hundred when sold as non-runners parts only cars!
Ya done good!
In automotive electrical, of course you always start with properly charged battery, and check your fuses. If that all checks out, it's time to put on your thinking cap and start troubleshooting.
First step, check to see if they light when you apply voltage to the bulb itself. They might just be burned out.
If they do, you need to figure out where the voltage is "getting lost", or more correctly, where the circuit is broken. In the electronics biz, we do what's called, "circuit splitting". This principle can be applied to the interior workings of electronic circuits, to automotive wiring, hydraulic equipment, and just about any other kind of problem.
The idea is to check the "far end" of the circuit first. In this case, the fog light bulbs themselves. If you give them 12v, and they don't light, replace them. This may solve the problem. If they do light, or you replace them with known good bulbs and they still don't work, you know the problem is somewhere between the bulbs and the battery. But where?
Pick a point that is functionally half way between the battery and the lights. (It's not critical that it's EXACTLY halfway, and remember we're talking functionally, not distance.) Test there to see if you get the expected results, which in your case would be 12v. If you don't, you apply 12v to the side of the circuit toward the bulbs. (We'll call this the far end of the circuit.) If the bulbs light, you know the problem is on the near end of the circuit, between your test point and the battery. So, pick a point that is halfway between your test point and the battery. Repeat as needed until you find the problem. Test, verify, split, repeat.
In this case of your fog lights, my first halfway test point would probably be the switch. Is it getting juice, and if so, is it putting OUT juice?
Then go from there.
Wiring under the seats has a tendency to get corrosion in connectors. Once you've checked the fuses (of course), look for that. If they are good, see the circuit splitting ideas above.
One more point - USE A TEST LIGHT. Meters are great, and should definitely be in your tool box, but sometimes, they can lie to you. If there is corrosion in a connection upstream (toward the battery), the meter may show 12v, but when you put a load on it, that voltage may drop to near zero.
This is because the corrosion can (usually, WILL) create a high resistance. This resistance will choke the flow of current down to the point where a device (fan motor, light bulb, whatever) will not be able to function. BUT, since a meter doesn't draw any appreciable amount of current, it will still show the correct voltage.
So, where corrosion may be a factor, use a test light.
Man, that is one SWEET deal! I see them going for seven or eight hundred when sold as non-runners parts only cars!
Ya done good!
Thread Starter
Seasoned Member
Joined: Oct 2013
Posts: 376
Likes: 5
From: Idaho
Year: 1991
Model: Cherokee
Engine: 4.0 Liter
I got a new headlight switch and put it in and everything works except my dimmer, it worked before but with the new switch it doesn't so I have no dash lights. Any guesses on why this is? And I tried cleaning the plugs and everything for the seats but that didn't work. And does anyone know how to put one of the glove box locks back together?
Edit: Scratch the first part, I just blew a fuse was all.
Edit: Scratch the first part, I just blew a fuse was all.
Last edited by ThatDude114; Jan 5, 2014 at 11:36 PM.
Thread Starter
Seasoned Member
Joined: Oct 2013
Posts: 376
Likes: 5
From: Idaho
Year: 1991
Model: Cherokee
Engine: 4.0 Liter
So I have a new problem to add the list, whenever my stereo is on and I try to roll down or up any of my working it cuts my entire stereo system out, and it also causes my clock to go completely out. This would indicate that there's a short in the power window system correct? And could this also possibly be the reason why power seats stopped working all of a sudden?
Member
Joined: Oct 2012
Posts: 147
Likes: 0
From: California
Year: 1988
Model: Cherokee
Engine: 4.6 Stroker
Here's a partial of my build sheet:
Auxiliary Transmission Oil Cooler
NHMP Speed Control
NMCP Heavy Duty Engine Cooling
PX8 Black Clear Coat
QX8S Black Clear Coat
RAAC All Radio Equipped Vehicles
RAFP AM/FM Cassette Radio
RCGP 6 Speakers
RDCP Power Antenna
SBAS Power Steering
SCGP Leather Wrapped Steering Wheel
SFAS Standard Duty Shock Absorbers
SGAS Rear Shock Absorbers
SUAP Tilt Steering Column
I have yet to find the other speakers though. They aren't in the rear doors or anywhere else I've looked. I just have 2 in the hatch and 2 for the front doors. It came with a factory amp too(I think). I have slightly more pressing concerns than that though, I bumped a wire and all of my speakers went silent and now my receiver won't stay on. And all the excess wiring makes it a total @#$&% to check any factory wires under the dash.
Auxiliary Transmission Oil Cooler
NHMP Speed Control
NMCP Heavy Duty Engine Cooling
PX8 Black Clear Coat
QX8S Black Clear Coat
RAAC All Radio Equipped Vehicles
RAFP AM/FM Cassette Radio
RCGP 6 Speakers
RDCP Power Antenna
SBAS Power Steering
SCGP Leather Wrapped Steering Wheel
SFAS Standard Duty Shock Absorbers
SGAS Rear Shock Absorbers
SUAP Tilt Steering Column
I have yet to find the other speakers though. They aren't in the rear doors or anywhere else I've looked. I just have 2 in the hatch and 2 for the front doors. It came with a factory amp too(I think). I have slightly more pressing concerns than that though, I bumped a wire and all of my speakers went silent and now my receiver won't stay on. And all the excess wiring makes it a total @#$&% to check any factory wires under the dash.
Thread Starter
Seasoned Member
Joined: Oct 2013
Posts: 376
Likes: 5
From: Idaho
Year: 1991
Model: Cherokee
Engine: 4.0 Liter
Follow this link: http://www.jeep.com/webselfservice/jeep/EmailPage.html
Just fill out the page and tell them that you'd like the build sheet for your vehicle. It took about a week to get mine. When you get the email it'll come up as Chrysler Group instead of Jeep.
Just fill out the page and tell them that you'd like the build sheet for your vehicle. It took about a week to get mine. When you get the email it'll come up as Chrysler Group instead of Jeep.
So I have a new problem to add the list, whenever my stereo is on and I try to roll down or up any of my working it cuts my entire stereo system out, and it also causes my clock to go completely out. This would indicate that there's a short in the power window system correct? And could this also possibly be the reason why power seats stopped working all of a sudden?
Thread Starter
Seasoned Member
Joined: Oct 2013
Posts: 376
Likes: 5
From: Idaho
Year: 1991
Model: Cherokee
Engine: 4.0 Liter
Welp, I'm slowly getting the problems worked out. I cleaned a lot the grounds which cleared up some issues. I still have to see if I can solder the wires for my window motor back in there because they broke off right at the motor. The stereo no longer cuts out either! I replaced my headlight switch and got it hooked up and everything but now there's a distinctive whirring sound coming from presumably the headlight switch whenever I pull the headlight **** all the way out. Before my old one broke it would occasionally make the sound and after I got the new one in I never heard it but now it's constant whenever the lights are on. Any thought's to what this may be?



