Tail lights dim

If you have encountered or solved a problem post here
Post Reply
martinN
Posts: 110
Joined: Sat Oct 10, 2020 2:26 pm

Tail lights dim

Post by martinN » Mon Jan 30, 2023 11:33 am

Couple of issues. My 2A lightweight lights. headlights and sidelights work fine but both taillights are very dim. Taking the lens off the bulbs are hardly on as if reduced power to them. Earthing issue? Brake lights are fine.
Also cold start sensor needs replacing. Any idea of part number.

User avatar
fv1620
Bake Off Judge
Posts: 2262
Joined: Thu Oct 06, 2011 2:16 pm
Location: GB-CMN (formerly UK91)
Contact:

Re: Tail lights dim

Post by fv1620 » Mon Jan 30, 2023 3:32 pm

Martin presumably your number plate light is also dim? I agree if the stop lights are ok the it does suggest it is not the usual earthing problem.

So the red wires from each tail light will join together at two snap couplers that have a red/black wire joining them. After this a communal red/black wire joins another snap coupler to a further red/black wire that goes to the terminal block. Then onto the light switch via another red/black wire. So be very suspicious of this communal feed system & its connectors.
Clive Elliott

Collecting military technical publications, researching into military vehicle electrical systems, licensed radio amateur since 1964 using microwave bands for tropospheric scatter.

Ltwtbarmy
Posts: 119
Joined: Fri Dec 13, 2013 5:32 pm

Re: Tail lights dim

Post by Ltwtbarmy » Mon Jan 30, 2023 4:52 pm

martinN wrote:
Mon Jan 30, 2023 11:33 am
Also cold start sensor needs replacing. Any idea of part number.
RTC5816 choke warning light
1984 RAF 109 GS 63KC41 RAF Catterick
1975 RAF Ltwt 75AM54 RAF Luqa and Wyton
1962 Army 88 GS 09EK34 DERR

diffwhine
Posts: 389
Joined: Sun Feb 25, 2018 9:28 pm

Re: Tail lights dim

Post by diffwhine » Mon Jan 30, 2023 5:27 pm

By cold start sensor, are you referring to the Otter switch on the front left hand of the cylinder head retained by 3 screw fixings (BA)? The part number for that is 545010.
I suggest you sit down and have a stiff drink before you open this link:

https://www.johncraddockltd.co.uk/searc ... l?s=545010

If you do a search on the Series 2 Club Forum, you should find discussion about changing the existing switch to a solid state system by swapping out the internals of your existing one to make a far cheaper and reliable fix. You will also need a new cork gask. the part number for that is 236022 if 1/16" thick or 535703 if its 1/8" thick. You can tell which one should be fitted by the lengths of the 2BA fixings. The thinner gasket goes with a 3/8" fixing and the thicker gasket goes with a 7/16" fixing.

With your electrical gremlins up the back end, does your vehicle still have the correct waterproof bullet system? You may need to change this in some areas to a more conventional civilian bullet system as those connectors are becoming unobtanium these days. I squirrelled as many a way as I could when the Wiring Harness Company made me a new harness for my 1968 Rover 1 and then I had to spend many happy hours (not) soldering on the correct bullets and connectors - a truly horrible job, but for the rivet counters, period and specification correct. Personally I would check the lot as if one part of the loom is going wrong, its likely the rest is thinking of following suit.

martinN
Posts: 110
Joined: Sat Oct 10, 2020 2:26 pm

Re: Tail lights dim

Post by martinN » Tue Jan 31, 2023 4:32 pm

Update.
The live feed from the battery to the ignition switch shows 12 v as it should vehicle starts no problem. As soon as I turn the lights on the live feed from the battery starts to cook at the junction box on the bulkhead in the engine bay. As feed power is trying to flow both ways. I have horrible feeling the ignition/ light switch is faulty. Opinions?

martinN
Posts: 110
Joined: Sat Oct 10, 2020 2:26 pm

Re: Tail lights dim

Post by martinN » Thu Feb 02, 2023 4:50 pm

Did a few more basic tests today. Checked the voltage at the rear light. Shows barely 3v. Ran a cable from the earth on the battery to the earth on one of the taillights. Makes no difference. Problem with the voltage to the taillights. I suspect faulty connection or earthing out on the voltage cable?

User avatar
AR4412
Maître Pâtissier
Posts: 8917
Joined: Thu Sep 22, 2011 9:31 am
Location: Bedford

Re: Tail lights dim

Post by AR4412 » Thu Feb 02, 2023 8:46 pm

Hi Martin,

If you disconnect the Red/Black wire for the tail lights at the terminal block and apply battery voltage to it, do the tail lights illuminate as they should? Does the Brown wire from the regulator have battery voltage on it at the terminal block? If, so, and you connect it to the Red/Black wire, do the tail lights illuminate as they should?

With everything connected as it should be, but with the tail lights disconnected at the six way switch or terminal block input, is the side light circuit okay, with the lights illuminating as they should when zelected? Do the headlights illuminate as they should when selected? Do all other circuits work as they should?

Regards,
For Those That Have Had To Fight for It, Life Has Truly A Flavour The Protected Will Never Know.

'First my weapon. Then my equipment. Then myself.'

Neil.

09FM98. 1973 Ex SIII FFR Now 3.5 V8 LWT Coiler.
55HG98. 1980 SIII FFR PARA RECCE. Ex 1, 2 and 3 PARA.
Td5 90 XS.

Post Reply