tarmactage

I've been searching for wiring diagrams for oil press/temp/volt gauges that I pulled out of a wrecked Coupe GT about 10 yrs ago. If I can resurrect them, I'd like to have them installed in my Subaru Legacy OB.

Any resources on the web with troubleshooting/test procedures? These haven't been installed since they were salvaged, (ostensibly for installation in an A1 GTI at the time) so I don't even know if they work.

Thanks!

Katman

The voltmeter uses only two wires, with it's +12V (+ terminal) on the top lead, and it's ground on the bottom lead. (Upside down T terminal). You could use that as is in the subaru.

The other two gauges would need a specific sender to make them work correctly. If you use a 'non-audi' sender, you'll probably have a difficult time to get tehm to read correctly. If you DO use the correct Audi sender, you may have problems physically mounting them in the Subaru. (For example, the oil temp sender is physically part of teh oil pressure releif system.)

BUt if you deal with that, The Oil & Temp gauges get their +12V on the bottom terminal (+ terminal), and their ground on the side terminal. (Upside down T terminal. The terminal that's under the nut)

Both the pressure and temp gage have the top lead going to the gauge sender (G terminal).

Both temp and pressure senders are variable resistance devices to ground, so you can 'sort of' make the gauge move to either of it's extremes by having the "G" terminal at the gauge either open (very high resistance) , or connected to ground (very low resistance). If those two conditions make the gauge swing to either end of it's travel, than at least the gauge end of things should be set up correctly.

(It may be that the gauge goes full scale when unconnected. But if so, it should go the other way when the gauge lead is grounded.)


Once that is working, you could try the same test at the sender end (either open, or connected to ground) of the wires, and you should see the gauges move as above. Then, (presumably!) connecting to the senders should work.

I *think* you connect the gauge to the 'G' terminal on the pressure sender. One terminal on the oil pressure sender gives variable resistance vs pressure, and the other terminal is a switch. That switch *may* be the low pressure switch, that *closes* around 0.3 bar.

(Opposite of a 'normal' oil pressue light switch, that closes when there is no oil pressure

tarmactage

Frank,

Many thanks for that wealth of information.

Given the considerations you outlined in your previous post, I'm tempted to buy new gauges at a site like eGauges.com. Seems like I can purchase a complete solution there - appropriate senders, etc.

Can anybody recommend any other places for gauges? (on-line, or brick & mortar) I'm in eastern Massachussets.


CJ