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MG MGA - Dim lights on the dashboard

Is there anything I can do to brighten my dashboard lights? I thought cleaning the contacts on my panel light switch would improve it, but it did not.
Tom D

From "Old Bill-67": MG Owner/Shady Tree Mechanic since 1962: (1.) Check the RHEOSTAT (s/a a POTENTIOMETER with 1 less terminal)that controls panel lamps. Crank it CLOCKWISE to INCREASE BRIGHTNESS. I
OLD BILL-67

Sorry about incomplete transmission! Hit the wrong key! The RHEOSTAT, I think, is part of the headlamp SWITCH and it can get inadvertently turned COUNTERCLOCKWISE (DIMMER!) (2.) If adjusting the rheostat doesn't help, unsolder the rheostat connections and check the resistance across the terminals with the OHMMETER RANGE of a Digital Multimeter (DVM). I don't remember the resistance value, but RESISTANCE SHOULD CHANGE WITH ADJUSTMENT "SMOOTHLY" W/O ANY "ERRACTIC JUMPING ABOUT"! If the resistance is erractic, REPLACE the RHEOSTAT, the swinging contact isn't making contact correctly and/or the wire-wound resistance wire is burnt, making a poor connection. You MIGHT be able to FIX a bad connection by taking the rheostat apart and bending the center contact so it makes correctly again, BUT WATCH FOR THE SMOKE IF YOU DON'T DO IT RIGHT!Only other thing I can think of is (3.) A BAD "GROUND" ("EARTH") CONNECTION for the DASHBOARD-TO-CHASSIS.
OLD BILL-67

Just a heads up on the erratic readings. If you use a digital meter, the numbers jump so fast when you move the knob, it may seem erratic. After cleaning with spray contact cleaner (move the knob a lot to wipe through any dirt and corrosion), measure the rheostat at several positions, resistance should increase evenly as you turn the knob counter-clockwise.

You can try jumping across the rheostat to see if the lamps get brighter. I assume that full clockwise is no resistance, so there should be no difference if you do this.
Tom

Tom
I had the same problem and found some higher output wattage bulbs at an autojumble. I do not know if these are still readily availible -you could try Holden. It also helps if can can stop the shed of light from the external bulbs down into the footwell as this can be distracting.
regards John
J H Cole

You can get halogen bulbs from www.lbcarco.com but they are very expensive compared to the standard bulbs. Another option is to disassemble the instruments and paint the inside of the cases with white or silver paint so that more of the light is reflected out of the case.

Jeff Schultz

Tom is right about possible erractic jumping around on some DVMs, especially the cheaper ones! Perhaps I'm spoiled by my more expensive FLUKE DVM with its FAST DIGITAL REFRESH RATE, extra digits, and BUILT-IN ANALOG BAR SCALE! No reason at all an inexpensive old-fashioned ANALOG Volt-Ohm-Milliammeter wouldn't do fine for most MG troubleshooting, my favorite being my SIMPSON 260 V.O.M. originally designed in 1937!
OLD BILL-67

I love my Simpson 260. I use it whenever I can. Works well all the time. Analog meter movement dampens electrical noise. And is almost as accurate as any of the cheap Digitals. Close enough anyway.

I have a couple of DMMs too. One was a kit I built over 25 years ago and is still running strong(after replacing and reengineering the LCD display). It has very good specs that rival a Fluke, 0.05% on DC IIRC. My cheap digitals have a spec of maybe 1% on a good day. The Flukes I leave for work.

Each has it's own place. Especially the 8 dollar DMM special with backlit LCD display. That place is the trunk of the MG where I can get a reading in the dark if needed. I figure on the road I'd be troubleshooting a problem not setting a control box.

Chuck
Chuck Schaeferf

This thread was discussed between 08/10/2005 and 18/10/2005

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