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Temperaute guage..Bi-Metal Resistance

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R6MGS

R6MGS

Yoda
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After finished the body work, went to move the LE and the temerature gauge is not working..same goes for the fuel guage but that only work half the time anyway....Thinking it was a fuse I checked and replaced all four fuses in the main fuse box and the two in the white plastic connectors found just below the fuse box....Still not working....I am begining to think this car is cursed! I checked the connections to the guage and enverything looks good. So now I've read every shop manuel I've got and still cannot get a good direct to move in....I've read about the Bi-metal resistance equipment and to my understanding the fuel and temp gauages are connected to a voltage regulator(WHERE IS THIS REGULATOR???) I guess failing that the only other thing I could check/replace is the temperature sensor itself(I did check the connection to it and it looks OK) Is there anything else I should check before I replace the temperature sensor??

Thanks
Zack
 
I've also found a BROWN wire that looks like it connects to the fuse box but will not slide onto any of the connections(even though it looks the same as the other connections going to the box) Where does this brown wire go to??? Is it my problem? or should it not be connected(only for air equiped cars?)?
 
Yep,R6MGS, You must locate and check the "VOLTAGE STABILIZER" before you go any farther.Perhaps an MG Type will inform you where it is located.---Keoke
 
Hello Zack,

the voltage stabiliser is a small rectangular metal box about 1 1\2" long by 3\4" wide with two terminals, one male and one female. They are often attached to the rear of the speedometer. The wire colour will be green and light green.

A brown wire is permanently live and originates from the battery side of the solenoid and feeds to the ignition switch, main light switch and maybe some permanently live fuses if you have any. Of course the wire you refer to may be non original and of the wrong colour for its function.

Alec
 
Thanks guys...I guess I'll test for power at the temperature sensor and work my way from their.

Thanks
Zack
 
Hello Zack,

the feed from the stabiliser to the gauge is actually light green with a green tracer and should read about 10 volts as long as the gauges (fuel and temperature) complete the circuit otherwise it will read battery voltage. If it does either of those then connect the sensor terminal to earth and the gauge should read full scale, i.e. full or hot depending on which gauge. Then check the regulated voltage which should now be 10 volts approx.

Alec
 
Alec, Unfortuantly I don't have a voltmeter...I used a circuit tester to test for power to the temp sensor and cannot get power...so now I am thinking it's the Bi-metal stabilizer...I think I found it on the inside firewall to the left side.... I have a light green/green wire to it along with a green wire and a black wire for a total of 3 wires, there is also one free terminal on the stabilizer. So now I want to test the stabilzer but am unsure of where to start?Is there any other test I can perform to help diagnose the problem?

Thanks
Zack
 
Hi Zack, the voltage stabilizer doesn't put out a constant 10 volts, it pulses a few times a second and averages out to 10 volts on the lug that the green/green wire goes to. Usually the failure is it either puts out no voltage, or it's stuck at the 14 volts or so the battery is at. At least, that's how the Midget one worked; I'm assuming the MGB used the same. I built a solid state 10 volt regulator since mine was getting flaky.
 
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