Is this the cause of my intermittent tachometer issues.

[250bruh]

So I've been trying to track down a tachometer issue in my 92 f250 7.3 idi. The tach sensor is good. The wiring is good all the way to the TCU. the wiring in the dash has continuity as well. The back of the tach has been checked and any questionable solder joints re done.

When I start the truck the the tach is dead and the trans is stuck in a high gear unless I manually shift it into a lower one. After a a few to 30 miles the tachometer springs to life and the transmission shifts as normal. If I shut it down for even a moment the issue returns. Pulling my hair out.

 

[Clb]

Dang puters...
Sounds like Hal 9000 **** to me.

 

[IDIBRONCO]

Without knowing much about electronics, I'd say that it's a good place to start. It doesn't look too healthy.

 

[IDIBRONCO]

Dang puters...
Sounds like Hal 9000 **** to me.

So you're saying that he shouldn't go out any air locks in the future?

 

[Black dawg]

Make sure the tcm relay is functioning correctly.

 

[250bruh]

Make sure the tcm relay is functioning correctly.

How would I go about that? The big fuses in the engine bay fuse box are all good.

 

[Reggie f250]

Turn on the key and check for power and ground at the tcm connector. If you have that the fuse and relay are good.

 

[250bruh]

To bring this up to date. The relay and fuse were good. So I tracked down a refurbished trans computer off of ebay. Paid more for the computer than I paid for the truck lol. Got it plugged in and everything put back together. Started it up and I have a tachometer, which means I have an automatic transmission that shifts automatically again! I hope that is it for a while.

 

[rreegg]

The price of the truck is just the initiation fee…