another Temp. gauge problem

[JohnRod]

1976 C-20 Suburban, 350 2wd,
I have the same problem as several others with a wacky reading temp. gauge. the needle would go way past hot and then vary around. I ran a new wire from the new sender to the green wire just before the plug in. no change. after that, the needle would waiver when the turn signal was on, and the volt meter was way low, and the needle would waiver when the AC was on. so today I cleaned both Bat. terminals, the ground cable at the Alt. and ran a new #10 ground strap from the Bat.- to the body. and I cleaned the area where 2 wires ground to the emergency brake bracket.
the dome lite appears to be some brighter. the temp. needle no longer varies when the turn signal is on and the Volt meter is where it should be-engine running. so some progress.
however, the door jamb lite switch get hot. hotter than you want to hold on to!!! something, somewhere is really wrong. either a ground problem somewhere I do no know about or some type of feedback problem.
I have no idea what to do next. any help?
thanks Rod in AZ
PS, I cant download the wire diagram

 

[chengny]

1976 C-20 Suburban, 350 2wd,
I have the same problem as several others with a wacky reading temp. gauge. the needle would go way past hot and then vary around. I ran a new wire from the new sender to the green wire just before the plug in. no change. after that, the needle would waiver when the turn signal was on, and the volt meter was way low, and the needle would waiver when the AC was on. so today I cleaned both Bat. terminals, the ground cable at the Alt. and ran a new #10 ground strap from the Bat.- to the body. and I cleaned the area where 2 wires ground to the emergency brake bracket.
the dome lite appears to be some brighter. the temp. needle no longer varies when the turn signal is on and the Volt meter is where it should be-engine running. so some progress.
however, the door jamb lite switch get hot. hotter than you want to hold on to!!! something, somewhere is really wrong. either a ground problem somewhere I do no know about or some type of feedback problem.
I have no idea what to do next. any help?
thanks Rod in AZ
PS, I cant download the wire diagram

Does the door jamb switch on the other side get hot too? If not, then it may just be that the "hot DJ switch" is loose.

 

[JohnRod]

I replaced the driver side dj switch with a wrecking yard find. I cleaned the contact area [where the 2 parts separate]. dome/courtesy lites seem brighter and the switch does not get hot.
on a separate note, these are differences I found looking at trucks; on my 76, there is a black wire which fastens to the emergency brake bracket with a sheet metal screw. that wire is the ground for the gauge panel. I find that different years, that black wire is in a different position on the big plug in. so be careful. my truck also has a white wire grounded at the same place [probably part of the white/orange dome lite]. other years do not have that white wire grounded there. later years went to a tab with male spade connectors.