Thread: Voltage stabiliser issue??

Sounds like your issue is the instrument panel earth. I can't remember just how that is connected, but be aware that the issue may not be just the instrument panel as a whole but the earth interconnects among the devices on and in the instrument panel, and there may be more than one fault. Most likely a corroded connection, but could be a broken wire (and some earthing from accidental earthing). Also check that the chassis earth and engine earth are connected.

Because of the bolted and riveted together body, Landrovers, particularly as they get older, are prone to earthing issues, especially for circuits relying on connecting to the body.

Thank you John for your thorough answer. There about 5 earth leads coming out of the dash, all connecting onto the rear of the speedo post/nut. Does the voltage stabiliser get earthed by the screw holding onto the rear of the speedo? Can’t see any earth leads going to the temp gauge/fuel gauge though….. should it be earthed?

I can't remember, and I no longer have a Series 3 to check. Neither the circuit diagram nor the workshop manual are particularly helpful.

Yes, the voltage stabiliser is earther by being screwed to the speedo case on the S3. But the metal cases of the speedo and the instrument cluster should be connected by an earth wire which is then connected to a metallic part of the vehicle. On my 110 it is the steering column support from memory, but it does not matter particularly. In the absence or poor connection of this wire, they may be sort of earthed through other chance circuits, the most likely being the speedo cable. But this is not designed as an electrical connection, so it is neither very good nor reliable.

I suggest that if you have not got a multimeter, you get one, you can get them pretty cheaply and for this sort of problem solving nothing fancy is needed. (a test light is also useful).

Thank you John. Yes, I’ve got a multimeter and test light…… I’ll have another look at the earth leads tomorrow and see what I can find🤓

Hope these help.
Make sure the earths are clean and tight.
May help understand. If you know someone with some electronics skills a better replacement can be made.
How To: Replace Your MGB / Lucas Thermal Voltage Stabilizer

whitehillbilly

Thank you😊

Spent 3 hours today trying out all the suggestions….. unfortunately nothing worked. Can’t work out why I’m getting 20.6v out of the voltage stabiliser, when it should be only 10v?…. Guess I’ll have to bite the bullet and go to an auto electrician!

Are you aware that the voltage stabiliser (assuming it is the original) does not provide a constant voltage, but provides an average of 10v by switching on and off every few secondswith the on vs off periods giving the average? They get away with this because the gauges that are supplied by it are very slow response - for example, I noted on my 2a (which has a S3 gauge cluster) yesterday morning I had to wait about half a minute for the fuel gauge to show a steady reading. For the fuel gauge in particular, this is an advantage, as it removes the effect of fuel sloshing about in a part full tank. So if you just momentarily measured the output, it is not very helpful. (They work by a small coil of resistance wire heating a bimetal strip.)

And the voltage stabiliser will do nothing if it does not have a good earth (i.e. a return to the other battery terminal).

I don't see how you get a reading of 20.6v from a 12v battery.