Odometer works but Speedometer and Tachometer often don’t...

Strange issue. I turn my truck to ‘on’ and I can see the speedometer and tachometer needles bobbing above zero, than back to zero, than above again. During this time the gas gauge and temp gauge don’t move. After about 15 seconds, if I’m lucky, everything will ‘bob’ into place. If I’m unlucky, the tach and speedo will stay at zero. Now the odometer continues to tick up for miles traveled. Any ideas?

 

The speedometer signal is fed from the right rear ABS Sensor to the Skid Control ECU ( Part of the ABS Unit ) to the combination meter if it is an automatic transmission.
A manual transmission has a separate speed sensor on the transmission that ties to the combination meter.

The Tachometer and Odometer are fed from the ECU.

 

What he said! RR speed sensor or wires for sure is having an issue, being a 2005 I wouldn't rule out spiral cable issue as well. Usually speed sensor issues don't affect tachometer.

 

Hmm... My cruise control is also out, which I think I've determined is the spiral cable. Could the spiral cable being bad also be linked to the instrument panel?

 

Cruise Control is most likely the spiral cable. Unfortuately the spiral cable has nothing to do with the Instrument panel ( Combination Meter ).

 

I ignored the spiral cable recall when they sent the letters out. The first symptom I had from spiral cable failing was random ABS light, second symptom was random cruise control not working, then when all the warning lights on the dash started randomly coming on and off I brought it in for recall. The only time my speedometer acts up is if Right Rear ABS sensor gets damaged. Oddly enough, one time I had to install a Right Rear wheel bearing that didn't have a ring on it because that was all that was available and the speedometer still worked, the ECU just deactivated ABS. ABS light stayed on and for sure didn't have anti-lock brakes for a while, lol!

 

I maybe wrong, but I seem to recall that Auto and Manual Trans trucks have different speedometer sensors. I could be wrong, there’s been so many different speed sensor post, it’s hard to keep up with?

 

See if you were under the spiral cable recall..my 10 was. Free repair isn't a bad thing anyway

 

Here is the recall.
It’s worth inquiring about.
http://media.fixed-ops.com/toy_campaigns/c0b-dlrltr.pdf

 

Yes that is correct. The automatic get the speed signal from the Skid Control ECU ( ABS ) where the manual gets the speed signal from the transmission sensor.

 

If I would have actually looked closer, I would have seen that in the first pic you posted.
Thanks Jimmy

 

Manual speed sensor:

 

Well I just realized I post the exact same picture you did.
I am off here tonight. Too tired to pay attention.
Wow......