Another Wiring Problem

[DirksCuda]

I got power coming to the fuel gauge and the volt limiter and INTO the oil an temp gauges. With the key on I got nothing coming out of the grey wire for the oil an nothing coming out of the violet wire for the temp. I tried grounding the bezel and all the fuses are good. The clock and fuel work but nothing at the oil and temp at the bezel or under the hoodat the sending unitsI got the maual with the wiring but cant figure it out. In the manual for the ralley dash it shows a plug in at the top of the diagram but I cant see any thing that plugs in up There. Am I missing something. Even if the gauges where bad I should still have power there right Thanks Dirk

[70chall440]

Dirk - as I recall you will not get any power out of the grey or violet wires, they are sending unit feed wires. The sending units ground out incrementally as either the oil pressure builds or the temp rises. You should have a wire that runs from voltage limiter (small rectangular box on the back of the instrument cluster) that provides power to the fuel level, temp and oil pressure gauges.

In other words, the 3 gauges get power directly and the various sending units provide a ground. I do not believe these gauges take 12V straight, the voltage limiter I believe takes the power down to something like 5.5V.

[DirksCuda]

Ive got power at the gauges from the voltage limiter, to the gauges but the oil pressuer gauge should work as soon as the engine starts I would think

[70chall440]

Yes, the oil pressure should work as the engine is turning over and building pressure. So, if you have power from the limiter and the the wire to the sending unit isn't broken, then you are left with 3 possibilities; the engine isn't building pressure, the sending unit isnt working, or the gauge isn't working.

I would start by making sure the wire is continuous by using a continuity tester. I would install a manual gauge to ensure the engine is building pressure. If those check out, then you are left with a bad gauge.

[DirksCuda]

I had mechanical gauges hooked up anthe pressure an temp are good. The sending units are new. How can I check the continuity in the wire from under the dash to the other end at the engine. I did like they showed on the internet,took the wire from the temp gauge off an grounded it which should get the gauge to move but it didn't. And it said with the key on test the wire with a test light and it should pulse telling u it is getting 6 volts, but there is no power at the oil or temp wire. Im going to run mechanical gagues anyway but would like to get these working Thanks Dirk

[70chall440]

You have some options here as far as testing;

1. to check continuity of the wires you can;
    A. obtain a continuity tester (many different ones out there, but essentially they make a sound when the 2 leads are connected). Many testing devices (multimeters) offer a continuity feature.
    B. you can rig up a test light and try and put 12V through the wire to see if it lights up. You can do the same thing with a device that makes noise when 12V through it, I am sure there are YouTube videos about it.

2. you can check the sending units by running a new wire from the gauge to the sending you, doesnt have to be run nicely just from point A to point B (out the window, under the hood to the sending unit. This will tell you if the sending unit and gauge works.

I think there are some videos on line on how to test the actual gauges, you might have to make some testing equipment.