Archived Help, Lost my speedo and.............

[Desperado]

I lost my Speedo, tachometer, AC, and the alternator is only charging at 12 volts, the rig starts fine and all of the lights work fine. I checked all fuses and relays. What have I missed?

 

[Missouri Mule]

Desperado'

Check 12 valve forum, I left reply there. Hope it helps.

 

[Desperado]

Ok, I think it looks like the PCM so heres what I've done, checked the volts with engine off (12. 59), started eigine checked volts again (12. 46), with engine running unhooked batteries, engine dies faster then if I turn the key off. I also checked the volts on my dads 1991 CTD (14. 85) and on Ol Blues (14. 01) still not sure what may be the problem. Help!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[Mundgyver]

Check all the wiring in the steering column at the ignition switch. Look for any wiring that could be sheared off from the spade connectors. If you have a tilt wheel system, the harness were not long enough to allow for proper flex and strain relief on some trucks. -Good luck - Mundgyver -

 

[Bovine]

Don't disconnect battery!

Desperado,

Unhooking the battery while engine is running causes bad things to happen with electronics. This was an Old School test performed in pre-gizmo days.

I do think it is your alternator. Most likely the bridge rectifier or diode assembly (turns AC into DC).

If you haven't done it yet, have it bench tested for proper operation.

 

[d906670]

mine did this last year turned out to be the bat. signal to the pcm rotted in half. located under the engine compartment fuse box next to the drivers side bat middle of the harness.

 

[Desperado]

I took my pick-up to the dealer Monday, thinking worst case scenario (CPM), I get a call right after noon and they say that it is fix, Oo. I ask what they found bad , and they say that it was my crank position sensor, total cost less than $200. 00. I’m really glad it wasn’t the CPM at $500. 00 plus labor. Anyway I have my wheels back. Thanks for all the suggestions and help. You guys are the best.