drunk_on_dzl

Alright guys I have read lots about this but can't solve my issue. I just bought a 1998 cherokee sport 4x4 with an auto trans. The guages do not work. I have went through the simple stuff like the grounds a fuses. No luck. I tore the dash out and cleaned the pins and still nothing. I tried the relearn and the dummy lights will light up but the guages do not cycle. I started to test with a multi meter but I need some help. I want to check for bus signal next. Some points of interest. It has been wreck on the passanger side I found after taking the dash out. When it gets to what I think is op temp (no way to tell) it runs rough, spark knocks, and back fires. I do NOT have a "no bus" in the odometer. Also the blower for the heat is not working nor are the dome lights. But it does light the gauges up. The low fuel light is on. Last the right turn signal indicater works but not the left. Any help would be great thanks.

drunk_on_dzl

47 views and no help? Come on guys give me some ideas here. Also the blower doesn't seem to be working.

CCKen

Sounds like you have a real jewel there...

If you are interested in checking your CCD data bus here's a schematic you can refer to. The schematic shows all the modules on the CCD bus and a description of the pin-outs on the Data Link Connector. All the DLC cavities are numbered but you will only have seven cavities on yours.

You'll need a digital Volt/Ohmmeter.



Voltage tests are done with the key in RUN/engine off. The resistance read is done with the key OFF.

Using your VOM, go from pin cavity 3 to 4 or 5. You should read around 2.41 to 2.50 volts.

Go from pin cavity 11 to 4 or 5, again you should read 2.41 to 2.50 volts.

If any of these voltage readings are not within the range stated there may be a module corrupting the CCD bus.

Check for 120 Ohm resistance in the PCM. Go from pin cavity 3 to 11. You should read 120 Ohms.

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I know you said you checked the fuses, but...

12 volt (B+) supply to the instrument cluster comes from fuse #16 in the PDC. This is the Ignition Off Draw (IOD) fuse. Look on the inside of the PDC cover to locate the IOD fuse.

12 volts also comes from the ignition switch Start-Run output. This if from fuse #9 in the Junction Block (passenger foot well). Here's a schematic of the JB.



Check these fuses again.

Ground for the Instrument Cluster is at ground G108. It's located on the instrument panel frame near the headlamp switch.

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Have you tried the Instrument Cluster Actuator Test?

Refer to the attached table for instrument response.

ACTUATOR TEST

The instrument cluster actuator test will put the cluster into its self-diagnostic mode. In this mode the cluster will position each of the gauge needles at various specified calibration points, and turn all of the CCD data bus message-controlled lamps on and off at specified time intervals.

Successful completion of the actuator test will confirm that the cluster circuitry, gauges, and lamps are capable of operating as designed. However, there may still be a problem with the CCD data bus, the Powertrain Control Module (PCM), the Airbag Control Module (ACM), or the inputs to one of these modules. Use a DRB scan tool and the proper Diagnostic Procedures manual for testing of these components.

If an individual gauge does not respond properly or at all during the Actuator Test, the instrument cluster should be removed. However, check the gauge mounting screws on the printed circuit board for proper tightness before considering instrument cluster replacement. If the mounting screws check OK, replace the faulty cluster.

If an individual indicator lamp does not illuminate during the Actuator Test, the instrument cluster should be removed. However, check that the incandescent lamp bulb is not faulty and that the bulb holder is properly installed on the circuit board before considering instrument cluster replacement. If the bulb and bulb holder check OK, replace the faulty instrument cluster.

(1) Begin the test with the ignition switch in the Off position.

(2) Depress the trip odometer reset button.

(3) While holding the trip odometer reset button depressed, turn the ignition switch to the On position, but do not start the engine.

(4) Release the trip odometer reset button.

(5) Compare the operation of the suspect gauge(s) and/or lamp(s).

(6) The cluster will exit the self-diagnostic mode at the completion of the test, or if the ignition switch is turned to the Off position.

(7) Go back to Step 1 to repeat the test, if required.



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I'll see if I have the Instrument Cluster connector(s) pin-out drawing.

CCKen

Before running the engine again you should do some preliminary inspections of the engine cooling system. At minimum, check the anti-freeze level in the overflow bottle and check the level in the radiator when it's cold by removing the cap. There are cases of fluid in the overflow but the radiator being empty or low. Is the anti-freeze rusty looking?

Is there any written history of the plugs, wires, cap & rotor ever being changed? You may want to pull the plugs and inspect them. They should be Champion RC12ECC plugs or NGK ZFR5N plugs gapped at .035. Pull the distributor cap and see if the rotor is ate up and if the pins in the cap are ate up.

drunk_on_dzl

Thanks Ken. I will test all these. The cap rotor plugs wires and ALL fluids are new. Down to additive in the rear. This is by far not my first time with a project. This one is just a gasser and not my thing at all. As far as it being a jewel lmao. It is perfect for what I want and will not but on the road. I have a know good fuse in the IOD. All ground have been checked and cleaned. Am I reading the wire diagram correct in that all power comes through the air bag control mod?

CCKen

No, Everything come from the PCM. Each module feeds the PCM. The center wires shown in the schematic are the CCD Data Bus. The Air Bag Module happens to be one of the modules on the bus.

Here's the instrument cluster pin outs and a diagram that shows connector C1 and C2, and ground G108.

drunk_on_dzl

Pin 3 and pin 11 give no reading. I rechecked the iod fuse in the pdc. And also number 9 inside. What should the voltage be at the pdc for the iod fuse? It reads .6 volts? So knowing I don't have signal from the bus where should I start. Man I feel stupid but electrical systems are not my strong point. But thatnks for the help.

CCKen

Are you reading from pin 3 to pin 4 or 5 and pin 11 to 4 or 5 in the DLC with the ignition switch in the RUN position/engine off? If you getting no reading (volts) using this method, try going from pin 3 to chassis ground and read from pin 11 to chassis ground. If you get 2.41-2.5 volts on pins 3 and 11 going to chassis ground pins 4 and 5 ground point on the engine may be disconnected. With the ignition switch off, you can use your Ohmmeter to read from pin 4 to chassis ground. You should read continuity (just like if you held the Ohmmeter probes together. The DLC connector pins 4 and 5 are grounded together at the right side of the engine at the oil dipstick tube attachment bracket bolt/stud. This is ground G102.

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How are you reading the IOD fuse cavities, from cavity to cavity or from one cavity at a time to chassis ground? The IOD fuse cavity towards the center of the PDC is the hot side. The IOD fuse (16) gets its power from fuse #11 in the PDC (I know...here we go again). It's a 30 Amp maxi fuse. It feeds the Junction Block. I doubt that it's blown but check it any way. Fuse 11 is the third one up from the bottom (forward side of PDC) on the inboard row (driver's side) of maxi fuses. It's a 30 Amp dude.

The IOD should receive battery voltage (12 volts).

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Don't feel stupid...hang in there.

Jeep circuits are simple but really suck if you let them get next to you.

drunk_on_dzl

Alright I am back at it. I have 2.5 volts at the DLC. I ran the codes in an attempt to solve the running issue. I found P1694 which seems to be an issue with the bus between the pcm and tcm. Can someone give me some info on what pins to ohm out to look for a short? Also where is the tcm? I want to check from pcm to tcm. Help me out

CCKen

You can follow the steps in this article:

http://wiki.answers.com/Q/What_does_..._Jeep_Cherokee

Suggest you use a length of 18 ga. wire that will reach from the PCM connector to the TCM connector. You should use a helper to hold one end of the jumper wire to the designated TCM connector pin cavity while you read the resistance at the designated PCM connector pin cavity.

You'll be reading from TCM cav 6 to PCM cav C28, and from TCM cav 7 to PCM cav C30.

Here's the location of the TCM:



Here's the TCM connector pin out:



And the PCM connector pin out:

drunk_on_dzl

Do you think this could relate to the running problem or the cluster? Also the pcm has 3 plugs which is the one I am looking for?

CCKen

If this Jeep has been in a wreck, like you say, there's a possibility that whomever put it back together left some connectors or grounds loose. You should check every ground in the engine bay for security and every connector in the engine bay for security.

"When it gets to what I think is op temp (no way to tell) it runs rough, spark knocks, and back fires."

This is a serious problem. Like I said earlier, I wouldn't try to operate this Jeep until you can get all electrical problems ironed out.

PCM connector C3 is the Gray connector. One's Black, one's White and the third is Gray.

I'll post some pics of the grounds in your engine bay in a bit.

Cheers

drunk_on_dzl

I have looked at most grounds but if you can show me them all that would be great. Also I'm getting readings all over when I ohm out the pcm to tcm wires. Ill try again tonight. BTW Ken thanks for your help.

CCKen

Here's pics of the engine bay ground points. Each pic has a brief description of what is grounded at the points shown.

Did you check the groungd (G108) under the dash by the headlamp switch (shown in previous post)?

98Plum Crazy

I have a 98 that started to have problems with the dash cluster and after pulling to clean contacts like everyone recommends, nothing worked anymore, I would def check the grounds on both sides of the dash, there were 2 sets o them about 3 inches apart behind the dash on both sides about halfway up the dash. Also, cleaned or not, you should replace speedo connectors, my dealer had them for $7 each. Last but not least, spend some time to check the passenger side fuse block, a small hole above that is grometted was leaking on mine and in turn got water and crap into my fuse block, and since t is a bunch I layers or chrome plated copper isolated by plastic, I was getting crazy shorts all over and after replacing that, I am happy to say everything works in my jeep for now, obviously they were built to break and give us Cherokee guys something to do!