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Main Section => Workshop Wisdom => Other Land Rovers => Topic started by: DogDave on April 18, 2022, 08:53:37 AM

Title: Odd wiring conundrum - S3 ex military
Post by: DogDave on April 18, 2022, 08:53:37 AM
So completed the new bulkhead which required pulling the wiring loom to bits and through the old one, and back through the new one. Thought I had been meticulous in labelling everything and putting back where it should be.

I have electrics to start and run, side lights, wipers, dash lights and screen wash. Don’t have anything to headlights, indicators, hazards, horn or fog lights.

Working through it trying to figure out - it’s not the ignition switch  as the wires coming off that are live when should be, all fuses are tested and OK.

Anyone see anything similar at all? Tracing is difficult as when it’s gone from Land Rover to Marshalls to St. John’s and after various alterations have happened so wires are rarely the same colour at both ends now.
Title: Re: Odd wiring conundrum - S3 ex military
Post by: jonhutchings on April 18, 2022, 10:40:06 AM
you mention is ex military, but it sounds like it it's not a GS, maybe an ambulance? A few details might help as the wiring differs on some of the military versions. Did it have the 6 way convoy light switch ?
Title: Re: Odd wiring conundrum - S3 ex military
Post by: DogDave on April 18, 2022, 10:46:35 AM
Sorry, yes it’s a 1981 registered Marshalls ambulance - crash rescue version for RAF it’s 12 volt.

It does still have the six way switch - so sidelights are working on that switch - but headlights are not

Puzzlingly the dashboard main beam warning light is working even though there is nothing coming through headlights on either dipped or main.
Title: Re: Odd wiring conundrum - S3 ex military
Post by: Wittsend on April 18, 2022, 11:04:20 AM
The MoD 6-way switch is a nightmare to deal with  :shakeinghead

We must have a wiring diagram of it somewhere and probably one for the Marshall ambulance and then it's a case of studying the diagrams against what you have.

I doubt us armchair electricians can help that much....


 :bright-idea
Title: Re: Odd wiring conundrum - S3 ex military
Post by: DogDave on April 18, 2022, 11:58:09 AM
Ok thanks - I’d kind of discounted that as the sidelights were working but if it’s a known source of gremlins I’ll have a study of the diagrams on the website tonight and see if any clues to be had
Title: Re: Odd wiring conundrum - S3 ex military
Post by: Wittsend on April 18, 2022, 12:11:06 PM
The problem I have on the LWT is that the 6-way switch is covered in a huge, rather inflexible water proof sheath which makes looking inside it almost impossible as to which wires go on which terminals  :thud

If you are lucky you may have better access.


 :RHD
Title: Re: Odd wiring conundrum - S3 ex military
Post by: DogDave on April 18, 2022, 12:27:27 PM
The problem I have on the LWT is that the 6-way switch is covered in a huge, rather inflexible water proof sheath which makes looking inside it almost impossible as to which wires go on which terminals  :thud

If you are lucky you may have better access.


 :RHD

Nope exactly the same problem here. But then goes into a 6 way connector that can only be done one way so i had assumed had got back as it should be - but then easily something come loose in undoing and putting back.

I have horn back now as one of the wires going to the fuse box was wrong- oh and rear fogs have come back but not front.

Title: Re: Odd wiring conundrum - S3 ex military
Post by: Wittsend on April 18, 2022, 12:31:01 PM
Maybe some switch/contact cleaner in the connector block ???

 :-\
Don't use WD-40 or the like - use proper contact cleaner formulated for this job.
Or, at a pinch use some aerosol brake/carb cleaner.

 :spray_can


Title: Re: Odd wiring conundrum - S3 ex military
Post by: DogDave on April 18, 2022, 03:17:52 PM
Only have wd40 so a badge but tried that, and there are similar blocks to the indicator stalk as well so done them - still no change. Puzzle that no indicators either although it could of course be 2 different problems at the same time.

Think some time on a pc looking a diagrams will be the answer
Title: Re: Odd wiring conundrum - S3 ex military
Post by: diffwhine on April 18, 2022, 05:10:41 PM
This should be the wiring for a 6 way switch.
Have you got a military wiring diagram?
Title: Re: Odd wiring conundrum - S3 ex military
Post by: autorover1 on April 18, 2022, 06:50:05 PM
Is there an infra red switch as the headlamps go through that .
Title: Re: Odd wiring conundrum - S3 ex military
Post by: nathanglasgow on April 18, 2022, 09:25:55 PM
Fairly sure IR was a series 3 thing.
Title: Re: Odd wiring conundrum - S3 ex military
Post by: DogDave on April 18, 2022, 09:42:16 PM
I don't think it has a infra red switch - if it has I haven't found it yet (which is fairly plausible but i'd have thought I would if it was there.

I think next step is taking the connector block off and jumping the connections to see if the switch is faulty somehow using that diagram - that should tell me if the fault is the switch or elsewhere i guess.
Title: Re: Odd wiring conundrum - S3 ex military
Post by: DogDave on April 18, 2022, 10:10:07 PM
Ok pretty sure it’s not the switch. I can jumper the wires and amazingly the colours are right this time. Live is live, live to sidelights works, taillights work

Live to headlights - nothing happens - live to indicators nothing.

So something else is not as should be somewhere although why there should be anything between headlight and switch that would point to the combined indicator / dip main stalk I will attack that next
Title: Re: Odd wiring conundrum - S3 ex military
Post by: diffwhine on April 18, 2022, 10:49:54 PM
I'd certainly do checks round the dim dip switch. They can fail and potentially leave you without anything. The operation is the same as a civilian vehicle, so the wiring checks in the workshop manual should help. Easy one to check
Title: Re: Odd wiring conundrum - S3 ex military
Post by: Chris C on April 19, 2022, 10:06:19 AM
If the main beam warning light is working then you are getting volts to the dip switch so the fault is after that.  Presumably the light goes off and on with the dip switch?
Title: Re: Odd wiring conundrum - S3 ex military
Post by: DogDave on April 19, 2022, 10:49:29 AM
If the main beam warning light is working then you are getting volts to the dip switch so the fault is after that.  Presumably the light goes off and on with the dip switch?

Er well actually- just been out to make sure - on flash it is working as it should but ignition has to be on, whereas when headlights selected it’s showing for either dip or main. - but regardless of whether ignition on or not.

Also the horn which is on that stalk works fine but indicators don’t, but neither do hazards which are on a separate switch altogether.

There is a lot of cut and joined wire and dead ends so this has caused someone else problems in the  past I think -