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MG MGB Technical - dashlights

I am restoring a 1970 MGB and am in the process of putting the dash back together after recovering it. I currently have all the guages and switches in, except the tac and speedo. I have no dash lights. My headlights work. Do the dash lights come on with the head light switch and not have any type of reostat?

The dash lights should come on with the parking/side lights and the headlights. You should have a rheostat on the dash somewhere, I don't know where it is on the 70 US model. I have yet to find a good rheostat and have bypassed them on every MG I have ever owned. If you have no rheostat you should have a pair of spare spade connectors behind the dash where the rheostat should be, if you connect these together the dash lights should come on with the parking/side lights.
The Wiz

Don, The rheostat is located on the firewall to the left of the steering colum that controls the voltage going to your gas and temp guage, also your instrument lights. You also have a switch on the left side of the steering colum shrowd that allows the instr. lights to come on once you've turned the headlight switch on. I've just finished the dash electrical on my 70'B. If you have more questions I'd be glad to help. Lee
LH Keyes

My 1970 has an on/off slide switch on the left side of the steering wheel cowl. Don't ask why there's an "off". Maybe people like to guess if their fuel is low, their oil pressure is lost, their engine is hot, or if they're going slow enough not to go down the cliff below the sharp turn.

Dan Robinson

Thanks for the response. I had forgotten about that switch on the side of the column. I had rapped it over the top of the column while working so it would not hang in my face.

I have found that I have power to the hot side of the switch and power to the other side of the switch when turned on but still no dash lights. I also find that if I hook up my probe tester to the hot side and probe the other side, the probe light will come on. That indicates to me that I may have a short to ground some place down the line. Also with the lead hooked to power a hanging dash light will light up if I touch the outer light casing.

I will have to get underneith and try to follow wires. Wish I had thought to check this out before reinstalling the dash. It would have been alot easier to see where the wires go.

There is no rheostat on a '70. There is a voltage regulator (the bit that LH mentions), but the only dash light control is the switch on the shroud.

Someone told me that the switch is there so that in the late '60s in the UK, when you parked your car on the road and were required to keep the parking lights on all night, you could turn off the dash lights to reduce battery drain. Don't know if it's true, but I can't think of any other reason to turn them off -- it's not like they're blindingly bright! ;-)
Rob Edwards

Hi all.

As Rob says, it used to be compulsory in the UK to show a white light at the front and a red light at the rear when the vehicle was parked in the road during the hours of darkness. (This is no longer required under some circumstances).
I clearly remember that failing to get a car to start on a cold winter morning was quite a common experience, any reduction in the current drawn by the sidelights was worth having.

Many motorists used a small double-sided single bulb light (showing white to the front and red to the rear) that clipped onto the top of the side window glass and plugged into the cigarette lighter socket.
Electronics hobbyists would make a simple circuit using a photocell that switched the light on when it got dark, and off again when it got light.


I now have dash lights. All it takes is a little patience and some skinned knuckles.

This thread was discussed between 25/02/2006 and 26/02/2006

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