KyleM94

Except i don have an ECM and im 99% sure this PCM is good i got it from a reputable local dealer that does all of PDDs PCM/ECM Ground strap? Mine just bolts in but i have 12.4 volts on the ground pins when checking ground this is my wiring for WTS everything goes to PDC in engine bay then to PCM since its a 12 valve i do not have a ECM. Its just odd that the one fuse i had the tap blow on is also shared between both lights that are on when the key is turned to run im wondering if its just coincidence

Im having some late night thoughts looking at the FSM looking at the circuits for the wait to start and for overdrive light. Now if im understanding this correctly and thats a big IF, the power for the circuit goes from Battery A7 -> Fuse 14 -> WTS Battery A7 -> Fuse 14 -> OD indicator Now fuse 14 is the fuse i have a tap in that is the same fuse tap that blew (coincidence maybe) For the second half of the circuit then it would be WTS/OD light -> PCM So in this circuit the PCM is providing ground? if so the problem may be here how would i test the circuit at the fuse and at the pcm to make sure is functioning as it should?

Yes but i will recheck in the morning i have an external regulator on it right now since when this started it stopped charging but my voltmeter shows batteries fully charged when running

Gotcha makes sense ill have to pick some up and try it

So pretty much a straight splice from PCM to cluster. What do you mean by note polarity

Thats a perfect picture i have the knee panel pulled id like to not destroy my dash but if it fixes my problem then ill sacrifice some of it. Ill get them pulled sprayed and seated. I want to err on the side of skepticism so assuming this doesnt work then any other diagnostic to do? edit pulled them sprayed with cleaner and re seated them

Wiggled around the connectors and pressed them together to make sure i sprayed the PDC ones with some contact cleaner. Without pulling the dash i cant get to the others to spray them but i did find something interesting. I cant get any reading on fuse 1 in the dash junction block. It just says infinite its a 20a max size fuse. I pulled it out the connection isnt broken but it has what appears to be corrosion inside of the fuse i will include a picture could this be the culprit

Good readings at all 4 pins

Did some probing i have ABS,PCM,CTM modules un hooked i pulled fuses for airbag as well instead of unhooking module under dash cause i didnt want to fight with it. Radio left connected for now. I have 2.55/2.57 reading with multimeter set to 20v DC pin number 28 & 31 C3 PCM witch is CCD -/+. Grounds read good, power is good to PCM. I do not have 5 volt reference signal not sure it that’s important, ABS 2.53/2.56 and grounds test good. I cant get a reading on the ctm yet or data link but if they test good what would be next step

I definitely will check that ive pulled the tap out and set just a fuse in it and didnt notice a change it powers the color lighting for my guages on the tap they all work fine but definitely possible

So just to verify i should unhook all modules except cluster. KOEO plugs at PcM should be 2.5v +/- .01 V then i check the individual module plugs to see that they are all seeing correct voltage?

Fuses came out good, i will probe the CCD bus and post the readings i get

I have used that a little bit to try and troubleshoot ignoring the ECM section obviously. I know everything under the hood going to the PDC is good. Just out of curiosity there is no way to bypss any of the CCD is there to get speedometer/tach working again is there

I actually plan on converting to a 24v once i figure this issue out, i mostly hate the needle in hay stack chasing electrical issues. Im going to go out today and check fuses been little under the weather I will check for seatbelt module ive tried ABS and CTM i pulled the fuses for Airbag and the light came on but with them in the Airbag light is off and it doesn’t change anything i dont have the overhead console but im definitely going to look at the A pillar

Im hoping its a fuse i missed i had batteries out completely for 24 hrs while i waited to get my pcm. It is frustrating i hate diagnosing electrical issues, give me mechanical and im happy all day. I have the full FSM and skimming the wiring diagrams is a adventure all in it self.

I will do that in the morning, if i take the 12v cluster out and put my 24v one in i get the same codes and issues minus OD off light but that might be just cause its a cluster from a manual truck. If i unplug every module leaving just PCM and cluster that would rule out one of the modules causing the ccd network to throw a fit correct?

As title states im in serious need of help. Was driving along in my 98 12 valve when i lost all input from the cluster. I have done self check and the cluster passed and gives codes 920-921-999. I have cleaned grounds in engine bay, have a brand new vin coded pcm swapped in a different engine harness that i went through and cleaned every connection and re wrapped. I have swapped in a cluster from another 98 as well as a 99 24 valve. I have un plugged modules without any change checked relays swapped them around as well as checked fuses. One thing that is odd is usually everything i read with regards to no bus is the lack of a WTS light. On my truck KOEO the WTS and OD off are lit up immediately and dont go out then after a bit i get ABS/Brake, Low Fuel, and the seatbelt warning light. I really need help figuring this out to get my cluster back, this happened maybe 15 mins after i was messing with my pillar pod guages and one of then shorted out and popped the fuse tap that it was in, fuse 14 in the junction block but everything else worked fine and I’ve replaced that fuse and my glow shift guages function properly as well as all other electronics on the truck. Any help is greatly appreciated