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Overhead Console Computer

Thej87

NAXJA Forum User
Location
Wetumpka, AL
I have tried searching for this topic online and have had no success. I have 2 1990 jeep Cherokees with the Laredo package and the overhead console. The computers in both consoles have stopped working when they were at 18 and 19 years of age. When I took them apart, I discovered what appears to be 3 resistors that have burned up on the circuit board (circled in the picture below). Both jeeps have the exact same problem. I have obtained one from an early 90s Cherokee in the junk yard and it had the same problem. It seems that this is a common problem with these computer units with that age. I even took the unit to an electronics buddy. Without a wiring schematic or single line diagram, he could not fix the circuit. Has anybody else experienced this problem? Is there a way to fix the burned up circuit? What causes this to happen? Is there a way to avoid this problem occurring on a working unit? Any help is MUCH appreciated!


BlownCircuit.jpg

thej39
 
when mine went out in my 90 i grabbed a new computer/display from the JY. worked fine. if you can find one there i would give that a try
 
Would it be as simple as replacing the resistor? We have four XJs, '92, '95, and two '96s. All have OHC, all work fine. My '92 had an OHC from the late '80s, and it worked fine (it currently has a '95 model in it, cosmetically it was much better). If you can read the value on it, I'd say just swap it. If it doesn't work, you've lost a few minutes in labor, and a few cents at Radio Shack, if you can find one that still sells electronic stuff.
 
Mine burnt up in the same place on my '91 Laredo around 2006; completely gone.

I too went to the junk yard and grabbed a new one out of a '90 Laredo (after popping it open to discover it wasn't burnt up). $5 and I had a working overhead computer.
 
I have a 93 country with a console out of ??? Po put it in is there a way to wire up the clock and compass to work in my xj. All the lights work just not the display.
 
There is no clock, just the compass and thermometer. There needs to be a probe behind the front bumper, that plugs into a fitting somewhere near or beneath the battery. Make sure the multi-conductor cable is plugged into the back of the display, and it is plugged into the fitting behind the right kick panel.
 
I have a 1990 overhead console that I no longer use, if you mean a outside temp gauge and a digital compass by "computer". Mine also has 4 overhead lights, happy to sell you mine. Other than being a but dusty inside it works fine. It has a light gray cloth covering along with a garage door opener and glasses compartment.

Thanks,
Fred
Explorer 1
 
Just pull the sensor from the junkyard and wiring harness. Its all plug and play since all the jeeps already have them wired up for it. As far as the computer goes you can maybe find one from the JY or try fixing it. Should only cost a couple bucks and a few minutes with a soldering iron. Nothing to really lose trying I think.


BTW does anyone have a spare temp sensor they can sell me? I need the one thats behind the front bumper since the one I pulled from the JY didnt have the sensor still there.
 
Ah ok ill probably wait till the next JY trip and just get the sensor since I dont NEED it. Also wasnt aware they were sold at advance either. Thanks guys.
 
I have tried searching for this topic online and have had no success. I have 2 1990 jeep Cherokees with the Laredo package and the overhead console. The computers in both consoles have stopped working when they were at 18 and 19 years of age. When I took them apart, I discovered what appears to be 3 resistors that have burned up on the circuit board (circled in the picture below). Both jeeps have the exact same problem. I have obtained one from an early 90s Cherokee in the junk yard and it had the same problem. It seems that this is a common problem with these computer units with that age. I even took the unit to an electronics buddy. Without a wiring schematic or single line diagram, he could not fix the circuit. Has anybody else experienced this problem? Is there a way to fix the burned up circuit? What causes this to happen? Is there a way to avoid this problem occurring on a working unit? Any help is MUCH appreciated!


BlownCircuit.jpg

thej39

I would think that you could just replace them but if they're burnt, can you still see the colored striping on them at all? Once you have that, it should be a pretty simple fix. Since they're both not working and have the same issues, you could experiment on one and if that works then you're golden.

Also, since they both worked for almost 20 years, I wouldn't worry about "fixing" them so they'll last longer. 20 years is a pretty long time for something like this.

Maybe a nice member on here would pull his console down and get the resistor colors for you?

:conceitedPartial thread jack ahead.

I need the brackets that hold the console up on a 92 XJ. I bought a used one of EBay but don't have the brackets. Anyone have a set?

We now return you to your regularly scheduled topic.
 
I'm pretty sure the ZJ temp sensors behind the grille are compatible too.

Those are surface mount resistors and will not have color stripes. They will have a 3 (or for more precise parts with <5% tolerance, 4) digit code on top in extremely small print. Interpret it like so:
(first two digits) * (1 with <third digit> zeros after it)

i.e. a "221" coded resistor will be 22 * 10 or 220 ohms, and a "474" will be 470000 ohms.

They can be a pain to solder if you don't have practice soldering surface mount components. Those look like 1208 size parts to me, unfortunately I can't read the values off them from that picture.

If I remember I will read the codes off the same two resistors on the OHC I have sitting in my living room waiting to be modified to fit in my MJ.
 
I'm pretty sure the ZJ temp sensors behind the grille are compatible too.

Those are surface mount resistors and will not have color stripes. They will have a 3 (or for more precise parts with <5% tolerance, 4) digit code on top in extremely small print. Interpret it like so:
(first two digits) * (1 with <third digit> zeros after it)

i.e. a "221" coded resistor will be 22 * 10 or 220 ohms, and a "474" will be 470000 ohms.

They can be a pain to solder if you don't have practice soldering surface mount components. Those look like 1208 size parts to me, unfortunately I can't read the values off them from that picture.

If I remember I will read the codes off the same two resistors on the OHC I have sitting in my living room waiting to be modified to fit in my MJ.


I knew someone would know this stuff;)

I'm really surprised nobody is rebuilding these and making a little money on it. I work for an Acura dealership and we have a problem with the NSX heater control circuit boards. They are over $1000 new but a guy online rebuilds them for around $125. And those cars are low production models, unlike these units.
 
I knew someone would know this stuff;)

I'm really surprised nobody is rebuilding these and making a little money on it. I work for an Acura dealership and we have a problem with the NSX heater control circuit boards. They are over $1000 new but a guy online rebuilds them for around $125. And those cars are low production models, unlike these units.


Not many XJs came with the overhead console, and of those that did have it they are 15 years old now(in the style you posted) so its not like there is a high demand to fix those parts.
 
I just pulled out a spare one i had and the resistors are tan colored. Like its just a tan rectangle. Not even sure what kind of resistor to be honest. Also I just realized the chip in the console was made by texas instruments. Heres a pic of what I mean. Not the exact resisters that are burnt out on his but the one I can get a good pic of. It looks like the same resistors the tan colored ones with no numbers.

IMG_0849.jpg
 
Last edited:
Those are surface mount capacitors not resistors then.

You got lucky, I was sitting next to the OHC I mentioned in my last post when I read this. Those capacitors are part of the voltage regulator circuit, the regulator is the part with the heat sink on it and 5 pins immediately to the left of the capacitors. Unfortunately if those caps burn, it probably meant the regulator failed and fed 13.8 volts into all the circuitry downstream of it, which expects 5 volts. You are probably in for a whole new board.
 
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