new temp gauge, doesnt seem to work Options

[7391420]

I've posted this a few times, and after trying several methods it's still not working..

-new vdo temp gauge-with the numeric readout.

-It plugs right into the old plug but it's not reading anything after driving the car for a while

-the old gauge worked (so i know the wiring is good)

-I did at the time buy a new VDO temp sensor, do I need to install this to get the gauge to work? can I remove the old one and plug this one in? or do I need to fabricate a place to plug it in and wire it up?






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[Dave_Darling]

It should read something, even with the old sender...

Time to check some stuff. First, make sure you've got an oil temp gauge, not a head temp gauge. (They work on two very different principles!) Next, make sure that you've got +12V when the ignition is "on" at the red/white wire that plugs into the back of the gauge. Next, make sure you have a decent ground on the brown wire going to the gauge. Next, check the resistance of the wire coming from the sender. It should give you a definite resistance, though I forget the range. I think it might be about 3000 ohms when the engine is cold? It gets lower as the engine warms up.

If the resistance is infinite, the wire is unplugged or broken somewhere. If the resistance is zero, the wire is shorted to ground somewhere.

If all of that checks out, you may have a dead gauge. You can try substituting a potentiometer (variable resistor with a knob) for the sender--plug one end into the gauge and the other to a ground. The needle should move when you tweak the knob. If it doesn't, the gauge is dead.

--DD