98 t&c lx 3.8: no data at the cluster

QuestionEdit

QUESTION: hi roland its michelle aain. ok my husband changed the pcm and now its running starts everything. now just the dash is not working, he has 3 instrument cluster the original one and 2 other ones none of them are working well the lights on the dash work, he gets power at the plug but the tach,gas,speed,temp gauges dont work neither do the PRND & milage dont come up. checked the circut board soldered all on all 3 and still dont work.

ANSWER: Hi Michelle, The signals for all the things that don't work are carried digitally on the pair of twisted wires that come in on pins 9 and 10 of the cluster. The other ends are at the body computer which is the central 'brain' where all the signals are gathered together. It is located under the dash on the left side and is the rear section of the fuse box you find there. It has a couple of 40-pin plugs on the bottom which can be removed easily #once you take off the knee blocker and the under dash panel# and that have numbers etched to identify the wires. So if you want to check out the wires from 9 and 10 of the cluster you look for pins 34 and 3 on one of the two plugs #the other plug has numbers 41-80#. If the connections are good then it may very well be that one of the fuses that powers the body computer is blown. In fact you might start by checking all these fuses which power that computer: In the box under the hood: 19,22,28 In the box under the dash: 1,2,3,6 If all the fuses are good and the connecting wires from the body computer to the cluster plugs are good, then I would suggest that the rest of the twisted pair wires that branch out from the computer to: engine controller, the diagnostic plug under the dash in the same area, HVAC controller, message center, radio, anti-lock brake unit, transmission controller be checked for a place where the twisted wires might be shorted together. In fact, maybe the best way to find out would be to get a fault code readout using a plug-in reader to see if the body computer can identify where the problem lies. An Autozone or similar nationwide parts store will often do that for free, or for $40 or so at an independent garage. Get the fault code numbers and let me know. But I suspect a fuse may be the cause of the situation. Please let me know what he learns. Also, if you would be so kind as to rate/nominate me again I would be very happy. Roland

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QUESTION: thanks roland my husband is going to test these now. he has checked the fuses but hes going to do it again, we have read/heard that the instrustment cluster has to be programmed he has never heard of this . he wanted to ask you if this might be the case also. also he wants to know if he should try to use the pin to ground the alarm wire because the alarm light is still lit but it runs so he wanted your opionion on this.

AnswerEdit

Hi Michelle, The cluster is not programmable so set aside that idea. On the alarm light, that will need further investigation. So long as it isn't shutting you down I would not worry about it. You can avoid problems with that system by only using the mechanical push-buttons to lock of the vehicle until this is resoved. Roland