The Lotus Grand Tourers

Does anyone know what the spec is of the gauge lighting bulbs? And has anyone tried replacing them with LEDs?

The bulb has gone on my fuel gauge; since I'm about to pull the dash out to replace my heater matrix, it would be a good moment to replace the bulb, and if I'm going to upgrade to LED I might as well do them all at the same time. And it would be good to have the bulb(s) to hand before I start the work!

The parts manual gives it as A050M6188F for the minor gauges and the warning lights, and a different bulb, A089M6062F, for the speedo and tacho.

SJ Sportscars have the speedo/tacho bulb, but don't appear to list the other type. A Google search on the Lotus part number comes up with nothing. SJ's part listing doesn't show a generic part type reference, that might help me find an LED equivalent.

I did LEDs last winter. I'll find to eBay listings, but hey are very common sizes.
Tony

Thanks Tony. I knew they would be a common size, I just didn't know which common size, and I wanted to get them ordered before I pulled the dash out and could find out for myself!

Search BA7 S and BA9 S and T5 286. I think that covers the dash. Speedo and tacho are the larger 1. I think you need 3, 2 in Speedo and 1 in tacho IIRC.
T5 is the small dials. It is possible to find T5 wired sockets to replace the Brocken plastic bayonets that keeps the bulb in the gauge.

Tony

BA7S is for the clock if I recall. Think you only need 1 of these.
I did find though that different designs had very different levels of success.vill check my "one job jobbed " thread. These something in there about which worked best.

Me again.
Check towards bottom of page 10 of my job jobbed thread. Don't know how to paste link on my mobile Photos there of lit dash and which LED worked best.

Excellent - many thanks Tony

I changed mine in the early days. Had no dimmer control so the were on max all the time and would burn out in time

Final conclusion - job done, and I'm pretty pleased with it.

I originally looked to buy them from Better Car Lighting, as they seem like a really good business. But I couldn't ignore the fact that they were a lot cheaper on eBay, I ended up buying them all from a seller called LED Bulbs For Classic Cars. Great service, they arrived promptly. I ordered:

• 2 x BA9S for the speedo and tacho. One of these (I forget which) actually takes 2 bulbs, so I should have ordered 3 in total, but I have to say they both seem plenty bright enough with one bulb each, so I'm not too bothered and I won't be adding another one.
• 5 x 286 T5 for the minor dash gauges
• 1 x BA7S for the clock
• The whole lot above cost just £13.35

I didn't replace the heater controls bulbs, rather wish I had now as they are dimmer than the rest and so look a bit out of place. I'll have to find out what size they are first! Also I don't really want to pull that panel out again, reconnecting the vents is such a PITA. Not sure if there is a bulb on the cigarette lighter? Anyway, I didn't check or replace it if there is!

My feeling is that the bulbs are good and bright, but not too bright. Others might disagree, but they are still less distracting than modern car dashboards (although I still remember a Saab I briefly had with a switch for "night stealth mode" that turned almost all the dash off!). They are not dimmable - if you turn the dimmer down they stay the same, then suddenly go out - but I'm not bothered by that. They fill the whole gauge with light pretty evenly, you don't get any of that thing where the top half looks brighter than the bottom half. The shade of green is a pretty good match for the original gauge lights, but the brightness is different so I'd say you would see a clear difference if you changed some and not others.

Next I will do the interior lighting, as I find that really dim and ineffective, I'll check the bulb size and see what I can get for them.

I did take a before and after photo, but I cannot post them somewhere I can link to while I'm at work, I'll try and remember to put them up later when I get home.

I’ve just trialled fitting LEDs to a spare Heater Control box, shown below.

My 1st attempt replacing the original 3 filament bulbs with LED bulbs improved the amount of light but it was not even across all the graphics.

After finding and repainting a spare panel I looked at using LEDs on a roll which can be cut to the length required, sold on Ebay, such as these: https://www.ebay.co.uk/itm/374308743706 ... 3188024631


Click on thumbnail above to see full image

I decided on the layout to give the best light behind the graphics, cut the strip to the lengths needed and soldered wires to continue the circuit at the at the corners, as shown above. The strips are held in place by the sticky tape on the back of the LEDs.

Yet to fit in the car, but pleased with the outcome.


Click on thumbnail above to see full image

Thanks Richard

Looks like a good result.

You need to use the BBCode to get the pictures to show up in your post.

Here's the Before and After with the gauge lighting:





Yes, the photo makes it look quite bright, but in use it's fine, easily readable but not distracting.

I've now replaced the interior courtesy lights too - you need a 42mm "festoon" bulb for these. The photos don't really look any difference; in reality the LED is more of a clean white light, the filament bulb had a definite tinge of orange in comparison. It's a little brighter, but not much. The bulbs I bought had 4 LEDs, but there are options with more, if I was going again I'd go for something brighter.

Just curious but have you noticed a dull glow from the interior lights when the doors are shut? So dull you can only see when dark.

When I changed mine to LEDs I had this, caused by the time delay relay and wondered if I had a dodgy relay or they all do it.

Zag wrote: ↑

Tue Jan 30, 2024 17:23

Just curious but have you noticed a dull glow from the interior lights when the doors are shut? So dull you can only see when dark.

When I changed mine to LEDs I had this, caused by the time delay relay and wondered if I had a dodgy relay or they all do it.

Not noticed this. But the door lights are still filament bulbs, so there is still significant current passing through the system. Also my time delay relay only works about 1/4 of the time, which is too small a problem ever to make it to the top of my list!