Anyone ever had this happen?

[LandonL]

Alright, when I have all the lights on inside the dash, and the headlights and I hit the dim switch the inside dash lights dim, and the headlights brighten, and when you dim the headlights, the dash cluster brightens? Anyone ever had this happen? A wire backwards or something?

[68 short step]

sounds like a ground wire... is your wireing 35+ yrs old? sometimes the wire looks good on the outside, but the inside is corroded...especially a ground wire, that has a bad connection...

[68gmsee]

Probably bad ground connections. If you haven't done so already, go to the auto parts and buy several ground straps. I got four. Here's where I installed them.

Make sure the cab has a good ground connection from the back of the engine to the cab.
Ground strap from bed to the frame.
Ground strap from frame to the cab.
Ground strap from batter negative to core support.

I made sure I had a good clean ground connection from battery neg to engine and I placed an additional strap from engine to frame.

My lights work better, no more weird problems with stop and signal lights and now my amp gauge works!

[cdowns]

the dash cluster is supposed to have a ground wire from the back of the cluster to the firewall/it originally had a clampclip that went to the firewall it was always a poor type of connection //i always run a wire from one of the screws in the cluster then drill hole in the firewall seam and bolt the other end to it for a positive ground connection

[bigguy69]

i am having all kinds of crazy problems. look in the electrical section of the board under half of my dash works. some good info. i would post a link, but i dont know how.

[LockDoc]

Originally Posted by bigguy69

i would post a link, but i dont know how.

Try this to post a link...

When you have the thread open that you want to link to just click your mouse once in the location window (the one that has the http:// in it). The whole web address should highlight. Then hold down the "Ctrl" key on the keyboard and press the "C" key. That copies the link. Start your post on here and after you type in what you want to say hit the "Enter" key a couple of times to space down a couple of lines, hold the "Ctrl" key down again and press the "V" key. This will paste the link you copied into your message. When you post, (Submit) the message the link will be light blue and people can just click on it to go to the thread. Always paste the link into a new line and don't use any punctuation before or after it.

LockDoc

[mike16]

factory assembly manual shows two grounds from the engine to the body. another good one id from the distributor to the block, espcially if you got electronic ignition.clean them all up.

[ace of shades]

I don't want to high jack the thread but I have something along the lines but its my heater. I can run everything on and works fine, but with the heater on it drags down everything. I know its either a ground or a relay problem but I was wondering if anyone had this problem so I might have a general Idea where to start

[67ss&99ss]

Have you tried the resistor that is on top of the heater box inside the cab?

I too have a problem with the lights on my truck. They all work but when the truck is running they dim and brighten back and forth and I noticed that the amp gauge oscillates at the same frequency as the lights. I have a new ground strap running from the engine to the cab but all of the others are older ones. The ground wire for the battery is attached to the passenger side cylinder head and I made sure this was a clean connection when I put the engine in. Should I replace all the other ground straps with new ones or is here something else causing an issue? The truck has the original harness, but it has never been cut/spliced. I replaced all the bulbs and put di-electric grease in each socket so they are getting a good connection that is water tight.

[VetteVet]

http://67-72chevytrucks.com/vboard/s...d.php?t=378104

Just right click on the address bar of the thread you want to refer to then click copy, then go to the post you want to refer to that thread and right click again and then hit paste.

I vote on a corroded dimmer switch or poor connections on the high beam lights.

[68C15]

Originally Posted by ace of shades

I don't want to high jack the thread but I have something along the lines but its my heater. I can run everything on and works fine, but with the heater on it drags down everything. I know its either a ground or a relay problem but I was wondering if anyone had this problem so I might have a general Idea where to start

this sounds to me like the single wire that feeds power to the cab is getting a poor connection or the fuse near the battery is corroded.

[bigsnookmaster]

You cant have too many ground straps. I go to the local pull a part and get them cheap. As much as I hate to say it, the F--ds seem to have nice ones. My .02

[bigguy69]

http://67-72chevytrucks.com/vboard/s...d.php?t=378104

lets see if that worked, thanks for all the help guys