Coolant Warning Light - not working?

An alchemy of sparks, copper wire and earth

Moderators: User administrators, Moderators

Locked
Smudger38
Registered user
Posts: 32
Joined: 18 Jul 2010, 20:48

Coolant Warning Light - not working?

Post by Smudger38 »

Hi I wonder of anyone could shed some light on a problem I have. Since I bought my T25 last year the low coolant warning light has never come on when I turn the ignition. It is my understanding that it should flash a couple of times when you turn the ignition on as an indication that it is working. I have had a look at the back of the instrument panel, allthough I cannot work out if there is a wire which connects directly to the bulb, or is the wire part of the multi connector? The reason I ask is that there is one loose brown wire that is not connected to anything and looks like it may have been cut at some stage? Looks like the workings of a very dodgy mechanic as when I bought the van the coolant was low in the header tank due to a knackered dalek cap, which I have now replaced. As I am useless with electrics, if anyone knows how this bulb is connected it would be appreciated. Thanks.

User avatar
Aidan
Trader
Posts: 7074
Joined: 11 Oct 2005, 19:21
80-90 Mem No: 742
Location: Llanfyllin, mid Wales : )
Contact:

Re: Coolant Warning Light - not working?

Post by Aidan »

multiconnector
does the oil pressure light do it's thing ?
if so probably blown or missing bulb, 171 919 061 B is the red one for temp/coolant warning

Smudger38
Registered user
Posts: 32
Joined: 18 Jul 2010, 20:48

Re: Coolant Warning Light - not working?

Post by Smudger38 »

Aiden many thanks. The oil pressure warning light works fine when you turn the ignition. I will try changing the bulb!

User avatar
AngeloEvs
Registered user
Posts: 1345
Joined: 22 Nov 2007, 19:22
80-90 Mem No: 4709
Location: Upwell, Norfolk

Re: Coolant Warning Light - not working?

Post by AngeloEvs »

Does the Temp gauge work and are you referring to the small Red LED in it? If yes.........

The coolant LED is controlled directly from a small electronic circuit fitted within the temp gauge. There are three nuts at the rear of the temp gauge which secure it and connect it to the blue membrane circuit. The smaller one that sits centrally is the earth connection for this internal circuit. If this nut becomes loose, or the copper underneath has tarnished, or the the track damaged then the LED and the circuit that makes it flash will stop working as it relies on this connection to earth. Try connecting a small length of wire from the centre nut directly to a good earth point using a length of insulated wire with croc clips on either end and then switch on the ignition. If it still fails to work you will need to replace the gauge. The guages can be dismanteld with care but whilst the LED can be carefully replaced the small chip that drives it and responds to signals from the Level Sender Control Unit (43) cannot.
1987 DG Karisma LPG with remodelled interior

Smudger38
Registered user
Posts: 32
Joined: 18 Jul 2010, 20:48

Re: Coolant Warning Light - not working?

Post by Smudger38 »

Great will have a look at the weekend, just got back from Dub Aid - fantastic weekend

Smudger38
Registered user
Posts: 32
Joined: 18 Jul 2010, 20:48

Re: Coolant Warning Light - not working?

Post by Smudger38 »

Ok managed to repair the red led low coolant warning light today. Basically ran a wire from the small central connector on the back of the temp guage to an earth point. Now works fine and took about an hour. so glad it was not the bulb as I could not take the guage apart as it is a sealed unit. Thanks for all your help guys it is appreciated

Locked