Hello, I have a 69 convertible that i've owned for 6mo now. I can tell that the previous owner/owners have messed with the under-dash wiring a bit and that may be the cause of my problems here but, I thought i would solicit suggestions for a possible fix anyway. I have a prob with the fuel and amp guages located on the center console- 1) the fuel guage seems to work ok until you turn on the headlights in which case the guage needle moves to past empty? Could it be a grounding problem? Also, my amp guage fried one day while driving. That was fun.I was able to disconnect the battery before any other damage happened.I've replaced the guage, but when I go to hook up the connector on the back, the needle slams down to the peg. It sounds to me like a short or bad ground but i'm not sure where it's located. I can't seem to locate a decent wiring diagram that shows how everything is connected in the center console.What could be causing this??Any help would be appreciated.
Thanks!

The fuel guage is definately a ground problem. When the sender is grounded, the guage reads empty. Check the grounds around the tail lights in the trunk. Also check the ground coming off the tank itself.

The amp guage is hooked up this way:
Black wire (14ga) to connection block in front of battery thru a fuseable link.
Black/white stripe (14ga) to horn relay thru a fuseable link also.

As for the fuel gauge, it sounds like one of your guage light wires is grounding to something under there when you turn on the lights. I had this problem when one of my gauge light sockets came apart and the power wire was touching ground back there anytime I turned on the lights. The fuel gauge did exactly as you described.

Just a note - I replaced the more dangerous amp gauge with a voltage gauge. Just got a voltage gauge from a later GM and riveted the stock faceplate to it. (Many GM gauges are the same behind the faceplates.) I just changed the face to have 8,13,18 (volts) on it instead of the 0 in the center that was originally there. Changed the wiring to just have a ign. hot wire going to the correct terminal on the back of the gauge and grounded the case.

Ray

Thanks you guys for the quick response. I'll check it out and let you know what I find.

Thanks,
Grant

<BLOCKQUOTE>quote:</font><HR>Just a note - I replaced the more dangerous amp gauge with a voltage gauge. <HR></BLOCKQUOTE>

For about the thousandth time. The stock 69 "Ammeter" is not an ammeter at all but a millivolt meter marked in simulated amps. The guage reads the VOLTAGE difference between the two ends of the 10 gauge main battery wire connected to the positive terminal of the battery and the main distribution terminal on the horn relay.

As stated above one wire on the gauge is connected to the terminal block infront of the battery, the other lands on the same terminal on the horn relay that the #10 red wire does. There are fusable links in each of the two leads for the gauge. It will not set your car on fire, anymore than any other circuit in the car would.

Never, ever, ever install a true ammeter (one that is wired in series with your main battery wire, or alternator output wire) in your car. You just asking for a fire if you do that.

If you wire the stock gauge in series with your alternator or battery chances are you will fry it. The windings are not rated for much more than a couple of amps.

If your gauge is pegging downscale it means that there is an open circuit in the leg connected to the horn relay. The wire might be connected to the wrong terminal, there may be a loose connection where it goes thru the firewall, or into the console, or at the guage itself.

Heres a wiring diagram:
www.townisp.com/~markcanning/camaro/HOODWIRE.JPG (http://www.townisp.com/~markcanning/camaro/HOODWIRE.JPG)

The gauge wires are marked with small dots on the black (B) and black with white tracer (B/W) wires near the terminal block and at the splice near the voltage regulator and horn relay.

Fuel gauge problem is a bad ground under the dash. the gauge cluster should be grounded to a screw into the floor under the console. There should also be a jumper wire from the front gaage mounting plate to the rear plate so both plates get grounded.

------------------
Mark Canning
1969 Indy Pace Car
350/300HP RPO Z11
My 69 L48 - 350/300HP Engine (http://www.townisp.com/~markcanning/camaro/transparent%20air%20cleaner3.jpg)


[This message has been edited by Mark C (edited 07-30-2002).]