Hello I just registered. I know nothing about the Ram 1500 line of trucks. I need my head examined for buying something I know zilch about! I have a 99 Ram15004X4 with a little over 100k. When I bought it the alternator wasn't charging. I bought a new computer and that didn't resolve it. I then had a mechanic install an external voltage regulator. I would've done that myself,but I'm recovering from hand/wrist surgery. The cluster is crazy. Tach and speedometer jump back and forth. The odometer flashes. If I engage the parking brake the needles fall and the odometer stops flashing. I bought another cluster and it does the same thing. Any help would be appreciated.

 

You have a bad connection somewhere.... or a bad ground, or both..... You can download the factory service manual for your truck from here. It makes working on the electrical MUCH easier.

Did the external regulator solve your charging issues? If it did, your replacement PCM also has an issue. Unfortunately, its an all to common failure. Still don't understand why Dodge put the regulator in the PCM..... Just seems like a bad idea to me.

Going to move this to the Second Gen Ram section for ya. Welcome to DF!

 

The tow driver connected the jump cables backwards. I replace the fuseable link. The external voltage regulator did the trick. I hear it's a common fix for when that portion of the PCM goes out. Thank you for your help.

 

Fixed then? That would be good.

 

no. The cluster is still messed up. I'm thinking the cause was the jumper cables being reversed.

 

Shouldn't smoke the cluster....... and since you have two that are doing the same thing, gotta be an issue with the truck somewhere. On the 99, everything on the cluster is driven by the PCM on the Data bus. (pcm tells the gauges what to to.) So, if they are all freaking out, likely a poor connection on the communications bus. Check the connectors at the back of the cluster. Also check cluster grounds.

 

Thank you. Will do. I'm trying to think of what could get fried by reversing polarity.

 

What fuse able link?

 

May want to move the wires/connectors on the pcm and see if that does anything. Definitely sounds like a connection problem.