Gauge questions!!! (Sorry a little long)

[jorgensensc]

I'm rebuilding the gauge cluster tonight and have a few questions.

1) How can I test my fuel gauge, amp gauge, and temp gauge off of the cluster?
a) My fuel gauge is always giving me off readings. I know the sending unit is good, and the wireing is good too. It moves with fuel consumption, but full is 1/8 below full, and empty is 1/8 above half. Currently it reads 86 ohms between the posts without a resistor, with a resistor 86 ohms. Resistor itself reads 86 ohms seperate. This is all off of the gauge cluster with no circuit board.
b) My amp gauge reads just past the middle all the time (even when off of the cluster). I've heard about 2 fuses somewhere, but I don't know where they are located. I will admit in a moment of stupidity (not knowing the difference between ammeter and voltmeter) I hooked a pos. to one post and a neg to the other post off the bat for a split second (off the cluster). I saw smoke and immediately removed it. Did I damage the ammeter enough to make it not work? I see the inside plastic that the wires wrap around is a little melted, but everything still appears O.k. By the way the ohm reading between the 2 posts is 0ohms.
c) The last gauge is the temp gauge. I recently replaced the sending unit with a new one (yes it is a gauge one) and the gauge doesn't want to seem to read anything. It worked for awhile, but even when engine cold it would read at the 2nd tick past cold, when warm would go straight up and down. I checked the wires, they are good. Here is a strange part. The 2 posts that connect by resistor (resistor alone reads 86ohms) read nothing until you add the resistor, then they read 86 ohms. The other 2 posts that connect to the circuit board read 46 ohms (off the circuit card) I am much confused.

Sorry this is so long, but I did a search and didn't get any really good answers. Thanks in advance for the responses and for taking the time to read this thread.

[cableguy0]

i always thought gm fuel guages were on a scale of 0-90ohms that maybe where your problem is. i dont know for sure just throwing out a suggestion

[SWEET7T]

For your ammeter, to test it, you can hook it up like you already did on your battery, but you need to put a 'load' in the circuit. You could put a 12V light in the circuit, then it will read either charge or discharge (depending on which way you test the gauge).
The fuses are in the engine compartment. They are 4A mini glass fuses (super super short). There is one near the battery, a wire comes off of the junction block and heads toward the driver side of the truck on the radiator support. The second fuse is on the driver side, in the same place. It will be sticking out of the wiring harness that is above your driver-side headlight.

I don't know what to tell you about your other gauges... Sorry... Good luck!

[jorgensensc]

TTT

[john]

You probably did fry the ammeter hooked to pos-neg wires. The ammeter shows current flow on the pos. side. I tried to post a wiring diagram showing 4amp fuses but board won't let me. I get a board error message. If needed I can Email them John