97 ram no tach or speedometer
 

I have a 97 dodge ram cummins 4x4 with a manual trans. The other day i put a radio in it and now i dont have a speedo or a tach. I also dont have a wait to start light. Would the radio have something to do with this? The radio and everything else works fine just no tach or speedo and wait to start. So did i screw something up when i wired the radio in or is it just a coincidence and something else is wrong? The wiring harness i used is just a simple two plug that you just match the wire colors and i checked and double checked and it is right as far as i can tell. I can unplug the radio and plugs and the tach and speedo still doesn't work.

There are no fuses blown and no lose wires that I can find.

Is it charging still?
Cruise control not working?

If both of these are out as well.
If so, it sounds like your PCM took a dive.

I have a few spares if you need one, PM me.

Can you tell if it is still charging? How about cruise control?

Perhaps the IOD fuse blown?

Iod is ok but it's not charging. The cruise doesn't work either.

Sounds like all the stuff the PCM does, doesn't work, so it is most likely shot.

Before you go wild, check for voltage on the engine speed sensor, without it, nothing works. I believe it is 5V, gotta go look at the wiring diagram............... Anyway, I would wring out wiring before I would condemn the PCM.

I got about 4 volts at the plug.

so does that mean its the pcm?

All I know is if ALL the things that the PCM controls stop working, I change the PCM out and it has always worked for me.

Info, you will have to find the wiring issue, I still doubt it is the PCM.

Attachment 45251

Before you go all credit card and buy expensive stuff, check all the wires around where you did the radio install. You would certainly feel like an idiot if you spent hundreds on a new PCM only to find you had pulled out a plug.

I have checked everything i can think of and everything is fine as far as i can tell. So if i buy a used pcm can i just plug it in and it will work?

Like I said before it sounds like a bad PCM to me.
As EVERY function the PCM does, is not working.
I do HAVE spares '97 NV-4500 PCMs in my shop.
PM if you would like buy one, to try swapping PCMs.

Well took the truck to a shop and had them put a pcm in the truck and guess what didnt change a thing. So i got no rpm gauge no speedo and no charging system any more ideas?