I have a 98 2500 with a 12v. NONE of my gauges work, the warning lights work though. When I check the codes on the cluster I get 920, 921, 999. I took a PCM out of a 97 and it's the same story. PLEASE HELP

 

You would probably get a quicker response from the HELP forum or the 1st gen forum.
Obiviously you checked all the fuses?
Oh WELCOME to the DTR. Someone who knows will chime in shortly.

 

Its a '98, this IS the correct forum, the 1st gen 12Vs are WAY differnt than a 2nd gen 12V.

 

Not sure if the 12Vcan throw injector pump or other codes

didnt know if it was available per say with anything else, I do know this tho, I have had a PCm fail on me and it started with overcharging the heck outta my system (GEN light) then all of a sudden gauges and what not went Kaput...

U have to get a pcm from a 98 most likely to solve ur problem, and u have to get it programed, im not sure if that will solve ur problem, but it did for my 96, at a total cost of almost 800 dollars for everything programing, instalation, and PCM module...

Rick

 

The '97 PCM will not work in the '98.

Did you check the instrument cluster fuse in the fuse box?

DTC 920 and 921 indicate the speedo is not receiving speed and distance signals from the PCM

999 indicates there may be more problems than that.

Did you do the Diagnostic test, and did the test actuate the various gages?