Replace dashboard bulb - how to and bulb brightness query

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sharrar
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Replace dashboard bulb - how to and bulb brightness query

Post by sharrar »

Hello All,

1st timer needing to get into the dash, although managed ok with centre console access, so hoping will survive! On my 84 Excel I noticed the bulb that should illuminate the rev counter is out and needs replacing.

Is this an easy enough task? From past posts it seems rough process is there are 7 nuts to loosen around the dash, then ensure slack on the speedo cable and then pull the dash forward to allow access to bulbs. Can the slack required on the speedo cable be gathered from inside the car (ie. nothing to loosen / undo in engine bay?) Any tips / potential pitfalls would be highly appreciated!

Next question was on the bulbs themselves. Mine are pretty weak - the rheostat works but is on maximum brightness. I don't really want LEDs as they look too bright but wondered if newer, more modern bulbs might be a bit brighter? I was also weighing up changing the colour - possibly to blue or red. Has anyone had success with these colours (although I would guess it might sacrifice additional brightness going for non white?)

Last question was just to confirm the compatible bulb type is T5?

Thanks

Richard

richardw
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Re: Replace dashboard bulb - how to and bulb brightness query

Post by richardw »

First of all do you have Smiths or VDO instruments? If Smiths then bulbs that fit MGB, Triumph etc with similar instruments will work.

My dash (Elite S2 but similar) loosens with just 4 screws behind the removeable instrument facia panel inside the binnacle.

You should have a reasonable amount of slack in the speedo cable; mine has a hall sensor fitted (from Excel SA) and I can just undo the cable in front of the bulkhead so I’ve never tried. Just remove any ties securing the cable as it goes over the engine.

LED lights are not all bright. I now have warm white LED bulbs fitted and they are almost identical in appearance to the filament bulbs. I think everyone finds that the rheostat is virtually useless; just do the usual voltage and earth checks then bypass it if you wish!

Good luck, Richard
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sharrar
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Re: Replace dashboard bulb - how to and bulb brightness query

Post by sharrar »

Thanks Richard, mine are Smiths instruments. Would T5 be correct bulb size do you know?

That's good to know the speedo cable has plenty of slack I can see where it's clipped in on the engine and will release that to help things along. So then it's just pull the dash forward carefully and I should be able to access all the dial bulbs? (My hands aren't the smallest but given reasonable space that should be ok!)

I'll look for some LEDs - maybe a bright red. One thing on the rheostat presumably I can just leave connected and fully turned (I understand I will lose ability to dim but don't mind that but would prefer to leave it wired as it is if possible)

Thanks

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bash
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Re: Replace dashboard bulb - how to and bulb brightness query

Post by bash »

If you take out the wooden trim and the screws holding the metal instrument mount there should be enough slack in the speedo cable to push it thro the bulkhead and you can then get your hand behind the instruments to undo the knurled nob on the back of the speedo and the whole of the instrument panel can be released. Its on an electrical multiplug then if you want to take it out. My electrical harness is long enough to put the panel on the dash top.
Bash
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DavidOliver
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Re: Replace dashboard bulb - how to and bulb brightness query

Post by DavidOliver »

Hola Richard. First thought, might your car have optic fibre system for instrument lighting.
My car with VDO instruments , I have managed to free the panel enough to unscrew the speedo cable without pulling the cable through the bulkhead which breaks the seal around the cable grommet, a common source for water ingress into the footwell.
I bought LED bulbs from Classic Car LED´s and was very pleased with their service. You have a choice of colours I kept to green and replaced also the centre panel bulbs. Very impressed. Polarity of LED is vital when installing, just turn the bulb round. Brightness is fixed.
The original filament bulbs are coloured by a plastic cap over a plain bulb, might be hard to locate different coloured caps, which might also be a reason for brightness dropping with existing bulbs.
I also changed the rear light bulbs for LED, a bit more expensive but great sense of safety.

Dave the cog.

sharrar
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Re: Replace dashboard bulb - how to and bulb brightness query

Post by sharrar »

Thanks Bash and David, It seems that hopefully there should be enough slack in the cable and that gives me a bit more reassurance that I shouldn't disconnect anything!

I think I will go for LEDs and had read that polarity is important so will bear that in mind (thanks Dave). Out of curiosity has anyone mixed and matched both types of bulbs - such as keeping original bulbs for minor instrument gauges and putting in brighter LED bulbs for main speedo and revs? Or is that a no-no?

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DavidOliver
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Re: Replace dashboard bulb - how to and bulb brightness query

Post by DavidOliver »

LED bulbs are the same as ordinary bulbs for electrical connections, you can mix them.

Dave the cog

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Re: Replace dashboard bulb - how to and bulb brightness query

Post by Pete Boole »

Do LEDs for cars come with built-in resistors for current-limiting?

Pete

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