Head lights on... fuel gauge drops to empty

[Yobtaf]

Hey my neighbor has a 69 2 wheel drive. When he turns on the head lights his fuel gauge drops to empty what would cause this?

Also in one in socal he is selling this truck for $900 would probably come down on price.

 

[throttleissues]

I would start checking power connections to the dash and the bulkhead connector through the firewall. I'm guessing a poor connection is causing a voltage drop when the headlights are on. Still seems weird though.

 

[Kenny78]

How about the ground connection? I dont know how it is accomplished onthe tank

 

[abig84]

ive been having that problem for years. checked eveyrthing, re grounded everything.

mine only drops halfway, and when i put the left turn signal on it drops with the blink. right one is fine.... both turn signals only set off the left turn signal indicator on the inside but outside works fine... i gave up. post up if he figures out what it is lol. if just grown to live with it

 

[Kenny78]

Just curious, does a metal tank get grounded or do the straps bond it?

 

[chulisohombre]

i put an xtra ground strap directly from the guage cluster to the firewall.hooked it to one of the ground screws that hold in the printed circuit.gas guage works fine now.check all the different connections along the frame also.should be able to follow a brown wire from dash all the way back to the tank.it has a ground from the sender in the tank to the frame that i also replaced.been good for 12 years now.thats a good place to start lookin for problems.