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Tips
Tips

TR4/4A TR4 instrument lights

Adrio

Jedi Knight
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I know there is a thread on using LED replacements but I have a general question about the dash instrument lights. My TR4A dash lights are incredibly dim. I have bypassed the dimmer in case that was the problem. Before I chase this down any further and spend a ton of time, I was wondering if someone has any words of wisdom on it. That is, is this just normal for a TR4 or is there a known problem area that you could point me (like a ground that is no good etc.) to so that it saves me loads of trouble shooting time. They are so dim that with the garage door closed and the garage lights off I can hardly tell if the instrument lights are on or not. The bulbs are all new as they were missing when I rebuilt the car.
 
Did you get the correct replacement bulbs? A clean new bulb won't be exactly blinding but should be brighter than you describe.

You can easily pull the illumination bulb from the tach &/or speedo and directly ground the bulb holder to see how bright it realy is and whether poor ground is the issue (I doubt it as all your bulbs are dim).

On another list it was said that bulb number 1449 from an electronics store (or here: https://www.topbulb.com/search/results.asp?REF=5009) is compatible.
 
Bypassing the rheostat was a good idea, just ni case.

Wrong bulbs is a strong possibility.

My other suggestion would be to check your grounds behind the dash, for that matter everywhere you can find them. Remove & clean up, even if they look okay.

Alan Myers
San Jose, Calif.
'62 TR4 CT17602L
 
Thanks for the tips folks. In answer to your "do you have the correct bulb" question, I have used both bolbs from the local electronic store and now I have the bulbs Moss sells for this application in there.

The speedo and tach have a bit more light then the other four instruments but all in all they are much less bright then the ones in my TR3.

It sounds like I am going to have to chase this down manualy. I figure I have a poor ground or a voltage drop somewhere along the supply line. Any one know where all the connection points are before I get down there on my head under the dash with a volt/ohm meter held between my teeth.
 
I had a problem like that a long time ago. For two of my gauges the problem, in part, was debris and pieces of older broken bulbs inside the gauge housings. I know how that sounds, but it was really bad on my temperature gauge and oil gauge. If all gauges are dim, and if your rheostat switch is good, I wouldn't know where to turn other than the Voltage Regulator--the stabilizer is only for the fuel gauge and temperature indicator. Let us know what you find.
 
This has to be a grounding problem, the dash is not grounding to the body or corr. has damaged the connection. An added ground wire never hurt any circut, put one in and let us know.
MD(mad dog)
 
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