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MG MGB Technical - Intermittent gauges

I have what is probably a simple problem: my dash gauges go off and on randomly. I am guessing a poor connection on the circuit but don't know where to begin. Also, once I find the offending connection, is there a grease, or other substance to enhance these bullet connectors?
68 B cloth harness. btw.
Thanks!
Thomas Lennon

Check the voltage stabilizer, mounted to the firewall, under the dash. If you have a poor earth, it will cause this problem. Dielectric grease, spread over the connections, will prolong the life of the bullets indefinitely. RAY
rjm RAY

Ray-
Thanks...didn't even remember this as part of the circuit! I think I found it, a small rectangular box with 3 spade connectors on it. Drivers side, with green wires in and out. Sound right?
Tom
Thomas Lennon

Check out www.advanceautowire.com for the schematic for your car. The instruments on yours pass current through the gauge lamp switch. You probably have a simple switch on the left side of your steering column cowling that turns them off and on. It might have poor connections.
Rick Penland

Also check the earth loop to each gauge, it often gets left off. It should join all the gauges together via the clamp screws.
Allan Reeling

Thomas, that sounds like it. This controls the gauges, not the gauge lights. RAY
rjm RAY

The voltage stabiliser only controls the fuel gauge and possibly the temp gauge, if you have an electric gauge, as opposed to capillary.

Which gauges aren't working?
Dave O'Neill 2

Dave- oil, temp and fuel gauges are either on or off as a group.
Ray- the stabiliser is attached by a rivet, allowing it to pivot a bit. The book I have mentions it should be vertical, at least within 20 degrees to work properly. I will drill out the rivet and use a screw to hold it firm. This should improve the ground and orientation.
Tom
Thomas Lennon

The earth loop to the gauges is only for lighting (with the exception of the tach).

If it's operation and not illumination that is the problem, then is the tach going off at the same time? If so it is the green (fused ignition) 12v supply feeding both tach and stabiliser that is the problem, not the stabiliser. The schematics show the stabiliser feeding all three ancillary gauges on 67/68 American spec cars i.e. fuel, temp and oil. The green circuit feeds that first, then tees off to the tach and the heater fan, so if they are OK then the feed to the stabiliser must be OK, so the problem must be either the connection of those wires to the stabiliser, inside the stabiliser, or from the stabiliser to the first gauge which is the fuel gauge. Easy to eliminate the stabiliser itself, just connect the two connections on the stabiliser together.

According to the Parts Catalogue and the cars I have worked on the stabiliser is attached by a screw, not a rivet.
PaulH Solihull

This thread was discussed between 08/05/2011 and 15/05/2011

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