| OEM temp gauge not working [message #221096] |
Wed, 04 September 2013 00:49  |
Greenchevelless
Messages: 25
Registered: February 2013
Location: Tulsa, Okiehoma
Karma: 0
|
Junior Member |
|
|
So my coach has had an autometer temp gauge in it since I got it. I've always hated the thing hanging down under the dash and wanted to get the oem gauge working. So I shorted the OEM temp gauge sender wire and the gauge never moved. I preceded to removed the cluster and short out the sender wire at the gauge thinking maybe there was a break in the wire somewhere. This also did not have any response on the gauge. So I'm assuming its a dead gauge. unplugged the gauge always reads 1/4 anyway.
While I have no idea how the gauge actually works, I removed what looked like a resistor with a red square on the back of the gauge that is held on with 2 nuts, re installed the 2 nuts and shorted the sender wire again and the gauge pegged hot. I do not understand what the resistor does but i'm pretty sure its not making contact on the printed circuit on the gauge cluster. Any help would be awesome as I would like for it to work correctly. I already ordered the temp sender for it before I realized the gauge is dead.
1976 Palm Beach 26'
|
|
|
|
| Re: OEM temp gauge not working [message #221111 is a reply to message #221096] |
Wed, 04 September 2013 08:14  |
 |
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
|
Senior Member |
|
|
| Greenchevelless wrote on Wed, 04 September 2013 01:49 |
So my coach has had an autometer temp gauge in it since I got it. I've always hated the thing hanging down under the dash and wanted to get the oem gauge working. So I shorted the OEM temp gauge sender wire and the gauge never moved. I preceded to removed the cluster and short out the sender wire at the gauge thinking maybe there was a break in the wire somewhere. This also did not have any response on the gauge. So I'm assuming its a dead gauge. unplugged the gauge always reads 1/4 anyway.
While I have no idea how the gauge actually works, I removed what looked like a resistor with a red square on the back of the gauge that is held on with 2 nuts, re installed the 2 nuts and shorted the sender wire again and the gauge pegged hot. I do not understand what the resistor does but i'm pretty sure its not making contact on the printed circuit on the gauge cluster. Any help would be awesome as I would like for it to work correctly. I already ordered the temp sender for it before I realized the gauge is dead.
|
Greech,
The instruments GM used in this period were all manufactured by AC and are call "Air Core". The pointer is hooked to a magnet. It is balanced between two coils (electo-magnets) and stuck in place with some "grease" to damp the movement. Both windings are supplied with 12V power, one winding is grounded through that resistor you found and the other though the sender of interest. So, what you are looking at is a system that compares the resistor to the sender and does not care about the supply voltage.
Old AC instrument often fail where the winding meets the terminal screws. If you measure resistance across the three terminals, you will probably find one open. I have often been able to repair these with very careful soldering.
Good Luck
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
