Gauges not working


#1

My 2001 1 ton GMC pickup an has 121,000mi.

The Tach, Speedometer, volt meter and I think the oil pressure work correctly. My temp(water & transmission), fuel gauges do not work at all. The info center on the left side of the cluster only shows the red (not charging)light which is on all the time, but the volt mter indicates 14.5 volts and I have checked the batteries with a Fluke and it also read 14.5 volts. The transmission and milage indicator are visible when you turn the key just before it goes to the run position, but not visiblein the run/start position.

I have replaced the ignition switch and nothing change except my bank account got $150.00 lighter.

I have a mechanic friend that called me one day and asked me wha the symptoms of my truck were, I listed them and he said e had a truck in his shop with the same problem. I asked him on a later date what he found wrong so I could fx my truck and how much it cost. He replied that he didn’t have to fix it as th problem fixed itself.

Have you heard of this problem or can you point me in the right direction as to how to diagnose this problem

Thanks

Andy


#2

I assume you have checked the fuses in the dash and under the hood for any bad ones. The gauges you mention are usually tied to a voltage regulator to control them. That may be the trouble or there may be a power connection problem to it.


#3

Thanks I’ll check into the regulator. Isn’t it built into the alternator ona GM product? Oh Yea yes I have checked the fuses.


#4

Isn’t it built into the alternator …

I believe Cougar is referring to a different regulator. Car dashboards for years always ran on a lower voltage, like 5 volts - and they used a separate voltage regulator to control that. Newer computer controlled dashboards may be different so you’ll need to check that.

The idea behind the dashboard running on 5 volts was to make sure your dash reported accurate readings while you were cranking your starter and whenever you had a weak battery. If your dash gauges ran on 12 volts, you wouldn’t want something like an inaccurate gas gauge reading whenever you had a weak battery.


#5

sorry to bust your bubble but you are going to have to have a new instrument panel cluster (IPC). and it has to be programmed by the dealer most independent shops dont have this capability. i am a GM tech and have seen this and replaced plenty of them.