Goofy Gauges

[tvtegtmeier]

94 K2500 with 185k miles

On two separate occations (lasting about a day) - separated by about a week, The tach and speedometer bounce around - reading high then low and just generally flittering around.

While this is happening, everything else looks find. All the other gauge needles are steady, the cruise control continues to maintain a steady speed. It even happens while the transmission is in Park (engine running) and not touching the throttle.

I've gone over all the battery and ground connections, checked the connections to the Alternator. If I didn't see the needles dancing around I wouldn't know anything was 'wrong' as the engine makes no stumbling sounds and the cruise control continues to work normally.

Just looking for Ideas.

Thanks,
Tim

[dieseldaver]

Mine occasionally do that too. I've never found the culprit. I've checked all grounds countless times, cleaned the contacts, blah, blah, blah. I thought it was something to do with the transmission, but the cruise works perfectly. I've pretty much given up on it, and was hoping to find someone here on the list who's figured it out.
If you're at speed and hit the brake, does the speedo flicker? Mine goes down 10 kmh or so.

[pannhead]

same here as dieseldaver's blah,blah,blah..drove me crazy and got a used (good) gauge cluster (with less miles on the odometer ;) ) and all was well again...pulled the old one apart for entertainment purposes and never did see anything wrong

[portabull]

i would suspect the ignition switch. not
where you insert the key, but about half-way
down the steering column. it was about $14
and it fixed mine which had the same symptoms.
regards,
cliff

[catmandoo]

the speedo in my 92 with a 5spd will do it in neutral with the clutch out but push clutch in and it quits.

[StephenA]

maybe hairline cracks in the circuitboard or solder pads? Panhead: still got the old unit?

[charliepeterson]

Originally posted by portabull:
i would suspect the ignition switch. not
where you insert the key, but about half-way
down the steering column. it was about $14
and it fixed mine which had the same symptoms.
regards,
cliff Cliff's got this one right. It seems like more '94-'95's seem to have this problem than the other years.

[dieseldaver]

I thought the ignition switch was suspect on mine too. I changed it, but no change with the speedo.

[pannhead]

StephenA...yes i do,i'm holding on to it till the odometer catches up just in case IP goes out....i figure by spring its all your if you want it

[StephenA]

Thanks Pannhead- I'll take you up on it. Maybe I can find out why they fail.

[portabull]

dieseldaver,
if the tach and the speedometer are fluctuating,
i think it'll be the ignition, if the tach always
works, but speedometer goes to zero, i think it's
going to be the "output shaft speed sensor" (if
you have a 4l80e anyway). cowracer tipped me off
to this and it fixed mine.
regards,
cliff

[tvtegtmeier]

Thanks for all the input - both gauges actup at the same time. Sometimes fluctuating in unison about 1/4 inch, then going nuts even while in park. (both needles swinging wildly from one side to the other).

I'll wait until they are doing it often enough to know when I replace the ignition switch that it is fixed.

Tim

[dieseldaver]

portabull,

Thanks for the idea. I'll look into the output speed shaft some more.
Oh yeah, I don't have a tach (but I wish I did), so I can't compare the two gauges. Oh yeah, it is the 4L80E.

On another note, it was just above freezing last night. She started up this morning FAST. Looks like all that work I did on her last summer has paid off... tongue.gif