Testing interior light relay

[Barreti]

Can someone tell me how to test the big yellow relay.

I think it's knackered because the interior light isn't working with the doors any more and is on in whichever position I put the switch.
It was also warm when I pulled it from the car.

They seem difficult to find so I thought I'd test it before I hunt for a replacement.

And if anyone has found somewhere selling replacements would you let me know where you got it from.

Thanks
IanB

[Quinny]

Not sure about THAT relay.... But this is the way to check a normal relay...Put 12v across pins 85 and 86, and listen for the click....)

If it doesn't click its knackard....

If it does click, get a MULTI meter and put it on ohms...... Connect the leads to pins 30 and 87... Resistance should be 0

[Barreti]

Thanks Andy, I will give that a go

[spend]

It isn't wired like a normal relay, it's a timer & IIRC TVR only use part of the functionality built into it (1 or 2 pins aren't wired up). Sorry can't remember how it's wired up and don't have time to search through old notes for you.

[Loubaruch]

It is not a standard relay as Spend says as there are a few electronic bits inside. You cannot test it easily.

Notorious for failing, I believe it is a Ford part from a Fiesta/Escort 1990's era.

A candidate also for running your battery flat if faulty!

[Colin RedGriff]

Barreti said:

Can someone tell me how to test the big yellow relay.

I think it's knackered because the interior light isn't working with the doors any more and is on in whichever position I put the switch.
It was also warm when I pulled it from the car.

They seem difficult to find so I thought I'd test it before I hunt for a replacement.

And if anyone has found somewhere selling replacements would you let me know where you got it from.

Thanks
IanB

Hi Ian

Can't help with testing or a supply I'm afraid. But if the light is on whatever position the switch is in then i think you need to check the switch as well. There should be a position which breaks the circuit no matter what the relay is doing. In mine there a 3 positions, on all the time, off all the time and controlled by the relay/timer.

[Barreti]

Ah, didn't explain that very well did I.

I can turn the lights off (I have one in the passenger footwell too) with the switch in the centre position.
But up or down both turn the light on permanently.
So I think the relay is buggered.

I've done a bit of digging and found this information on the pin use

1 =Perm Negative - Any good ground on the chassis
2 =Switched Postive, from ignition
3 =Perm Positive
4 =Switched Negative (door switch)
5 =Negative Out (light bulb)

Though I am dubious about 4. being a Negative.
I didn't get chance to play with this last night but will have a go tonight.

[Bluebottle]

Barreti said:

Ah, didn't explain that very well did I.

I can turn the lights off (I have one in the passenger footwell too) with the switch in the centre position.
But up or down both turn the light on permanently.
So I think the relay is buggered.

I've done a bit of digging and found this information on the pin use

1 =Perm Negative - Any good ground on the chassis
2 =Switched Postive, from ignition
3 =Perm Positive
4 =Switched Negative (door switch)
5 =Negative Out (light bulb)

Though I am dubious about 4. being a Negative.
I didn't get chance to play with this last night but will have a go tonight.

Have you checked the door contact switches are working when the doors are closed?

[Barreti]

Yes, that is where this story started Bluebottle.
I had a chattering door solenoid which I eventually tracked down to a door switch which wasn't quite being closed properly (or opened for the pedantic, as its a switch) when the passenger door was closed.
I fitted small rubber spacers behind the switches to lift them a couple of mm, but the lights still wouldn't work correctly so I started doing some investigating.

Incidentally, I'm sure I've read recently mention of a door rubber. Is there something the door switch pushes on rather than just the paintwork?
I'm wondering if some kind of rubber pad should have been there and after the respray it wasn't refitted. It would explain the switch issue.

[spend]

Barreti said:

...Though I am dubious about 4. being a Negative...

Don't be, it is a switched ground.

The connections sound about right (no idea of the order though) to work the heater timer, and defeat it when the ignition is switched on.

Remember the light fitting switch has a common (permanent / battery) live and to switch it on the switch bridges to a constant ground or the timer relay controlled ground. Misunderstanding that maybe what made you dubious?

[Colin RedGriff]

Yes there should be a small round rubber pad on the door for the switch plunger to push against.

Not sure where to get them from but you could probably find something in B&Q like those pads used on kitchen cupboard doors.

[Barreti]

Something learned from both SPEND and Colin, thank you both. I love this place (providing I stay in this forum - its a bit scary out there otherwise )

[keith2.2]

My big yellow relay was the cause of my battery dying in under 24hrs. When it was tested, the light circuit was drawing - from memory - about 1.6A even with the engine off. Pulled the relay out and the battery lasted indefinitely - although I fitted an isolator for good measure.

[Adrian@]

Bespoke RUBBER PAD !!! TVR part number PAU-1...in production, the shells were/are mounted on 6mm rubber pads each of these would have to have a 10mm hole punched in to it!! a little round punched out piece of rubber ...TVR part number, Pick And Use one.
Adrian@

[MikeG]

Hi,
You may have already checked, but the door switched position of the interior light switch is on a timer control ( from that relay) and you either need to wait for the timer to switch off or turn the ignition on. This timer could make it seem that both switch positions are on all of the time.
Mike

[Hoover.]

No help on testing ......but it is a ford part fitted to Scorpio era cars from memory .....

Edited to just looked on eBay under ford interior light relay and handful came up around £25/ each

I do also remember talking to an auto electrician a few years back who implied that they do have a tendancy to stick open and drain the battery even when light is not on (probably balls st ... To justify his time in my footwell )

Edited by Hoover. on Wednesday 2nd July 07:04