Interior Lights

[Brewer]

Would be interested to hear from anyone who's replaced the interior Lucas bulbs with LED's in an S3. I went through this process with a kit containing 23 #987 replacements and 6 #281 replacements. The results are great - much brighter light on the gauges, but the number of bulbs in the kit doesn't seem to match my requirements. I have 8 #987's left over (used 15) and am lacking 2 #281's. So my question is: how many of each SHOULD be needed? The kit supplier isn't much help - they only confirm the number in the kit. Looking in the Jaguar parts manual, it appears that there are 15 #987's and 6 #281's (but I can testify my car uses 8). Looks like I'll be searching the innards of the dash for a third time...

[Craig Balzer]

I am considering installing LEDs in my 72 OTS.
It would help me immensely if you'd list:

• the 15 locations for the #987 replacement bulbs

• the 6 locations for the #281 replacement bulbs

On the #281's, knowing the 6 "known" locations will/may help others identity the other 2 location.

TIA
Craig

[Brewer]

Just went thru the dash again and yes, there are 15 - 987's and 9 - 281's - found an additional 281 hiding in the mass of wiring.

Here are the locations:
987's: battery, oil pressure, fuel level and water temperature - 1 each
turn signal indicators - 2
hazard warning indicator - 1
speedometer and tachometer - 2 each (4 total)
ignition, low fuel, high beam indicators - 3 total
brake fluid/handbrake warning - 1
That's a total of 15

281's: choke warning lamp - 1
choke detail panel - 1
clock - 1
oil pressure warning - 1
air/heater control panel - 1
seat belt warning - 1
rocker switch labels - 3 total
That's a total of 9.

Note that a car with AC and/or automatic transmission may have more; the parts manual is a little vague on this.

Also, the 3 that illuminate the rocker switch labels are hard to see and even harder to access; you may want to remove the radio mounting to allow the dash panel to drop down fully. Their lack of visibility may be why my kit didn't include them - an oversight by whoever designed the kit.

The swap is well worth the money and effort, IMO.

[MarekH]

Please don't use an LED for the ignition light.

If you absolutely insist, then make sure to use a bidirectional LED AND bypass it with a suitable resistor. Read up on how an alternator works if in doubt or look at my previous posts on the topic.

It's so serious that I've actually used an emoji for the first time EVER.

kind regards
Marek

[Craig Balzer]

Just went thru the dash again and yes, there are 15 - 987's and 9 - 281's - found an additional 281 hiding in the mass of wiring.

Here are the locations:

Super detailed response - very much appreciated.

I think I am in the right space to do this conversion.

[Brewer]

Craig, looks like you have an awesome opportunity in front of you. I hope you'll read this post before going further with the LED conversion.

I communicated with Marek H by email seeking direction to his previous posts on this topic. He very kindly replied and included detailed technical advice on why it's a BAD idea to use an LED for the ignition light. I will attach his comments below.

A word of caution - before purchasing my LED kit, I spoke with a tech person at the vendor's and asked specifically about this; he assured me it would be okay. Marek has convinced me it's NOT, and I will be reverting to a filament bulb (incandescent for those of us on this side of the pond) for this application only, retaining LED's elsewhere in the interior. If anyone would like NINE 987 LED's drop me a private nessage

Here are Marek's words of wisdom: "To produce any charging voltage, the alternator needs current to excite the field coil and this comes through the warning light so a directional LED isn't appropriate in this application. The light is also only on for a few seconds at startup, so there is no point upgrading it. The longevity of a filament bulb in this application appears to be in excess of 50 years as it is only used for a few seconds per trip.

The green turn signal jewels can use LEDs on the s3. The advice given to you here to not use them pertains to s1 cars. Once again though, there is no real benefit, as the turn indicator bulbs are almost never on, so no amount of tinkering will result in any real upgrade. The flasher and hazard cans work via a bimetallic strip which depends on drawing sufficient current to get them to make and break the circuit to cause the flashing, so switching to LEDs for the four turn indicators entails also changing the flasher can and hazard cans as LEDs all round don't draw enough current to make the circuit flash. The most sensible upgrade here is to simply swap out either the front OR the rear bulbs for LED bulbs if and when one of the filament bulbs has failed. That way, you don't waste money and still running one filament bulb per side means new flasher cans aren't needed.

There is no practical advantage in using LEDs for the fuel warning light or the high beam either. Use some common sense. These bulbs are almost never on or at least run form the alternator, not the battery, so there is little or no benefit in swapping them out.

My experience is that you need more illumination for the two large dials than you do for the smaller centre gauges."

Good luck, all, and thanks again, Marek

[Craig Balzer]

Brewer - thanx for that.
It all makes sense and I'll apply Marek's and your recommendations