wiring problems 72 1/2 ton suburban

[borob47]

I just bought a 72 Burb 1/2 ton . 1st. problem .gas gauge goes to full when you turn key on and is way past full with key off .I checked and it has a good ground . Also when you turn the radio on the gas gauge goes to 1/4 tank ? Also tail lights work good when lights are on low beam but go complete off when you turn lights on high . Also no dash lights ?/
Thanks in advance for any help Bob >> ivandale26354@aol.com

[LockDoc]

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Check and make sure all of your fuses are good and you don't have rust in the fuse holders first off.

Oh, and welcome to the board!

LockDoc

[Bigdav160]

Those symptoms suggest a bad ground somewhere.

The hard part is finding it.

[borob47]

Thanks guys . I will try both suggestions and I really appreciate it as this one is driving me crazy . This is an awesome site .

Bob

[Ol Blue K20]

Check all body to frame grounds. The high beam problem may just be a bad dimmer switch or bad bulbs but I lean towards dimmer switch. WELCOME!! to the board.

[borob47]

Hi GUYS . Still trying to figure out my wiring problem as I dont have any dash or dome lights and evrything is grounded and all fuses are good ? . I did find an orange wire hanging under the dash and with out having a color coded diagram I dont know where it goes ? How would I go about trouble shooting this problem
Thanks in advance Bob

[LockDoc]

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Wiring diagrams are here:
http://67-72chevytrucks.com/vboard/s...d.php?t=185856

There are Orange and White wires going from the fuse box to the dome light but they are two wires molded together and they are located under the drivers side sill plate..

Not sure what you mean by everything is grounded but just to double check, this was posted by GMCPaul in another thread. It is for a pickup but most of it would be the same for a Burb. Make sure you have them all.

""For your motor you should have the ground wire from battery connected to the passenger side front of cylinder head, then at rear of both V-8 valve covers going from last bottom rear bolt on each valve cover should be a groundstrap running from these bolts on both sides attached to the cab firewall, on passenger side front inner fender lower edge where it meets frame as it curves down should be another fround strap running from inner fender to frame, you should have a 4th ground strap running from frame to passenger side front cab support, and a 5th strap from rear bed cross-sill to frame, without all the proper grounding straps you can have a ton of odd electrical problems from some lights working intermittently, to poor charging, electrical parts failure, etc....
We carry the 5pc electrical ground strap sets with hardware to install on the following page of our web site if interested,
http://www.gmcpauls.com/Electrical.htm
GMCPaul ""

On the Suburbans there is also ground wires from each tail light to the body. They attach where the marker light screws come through the body on the inside. If they are rusted/corroded it can make all of the electrical system do funny stuff... I also run a ground from the front of the frame to the core support on all of my trucks..

LockDoc