Temp Light Flashing - Replace Relay 42 - FIXED?!

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bertnuggit
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Temp Light Flashing - Replace Relay 42 - FIXED?!

Post by bertnuggit »

I've been reading the long thread on Coolant temperature gauge - flashing red light+needle swing, but I'm lost!

Relay 42 is mentioned, if I replace Relay 42 in my T25 might that stop the temp light flashing and showing maximum temperature?

Worth a go?
Last edited by bertnuggit on 08 Feb 2019, 18:11, edited 1 time in total.
Red VW T25, 1985(B), DG Engine, 5 Speed, Petrol.

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Re: Temp Light Flashing - Replace Relay 42

Post by jrt »

If you pull the relay and the symptoms stay the same then it's the temp' sender circuit that is the problem. Maybe the sender needs changing.
Have you checked levels are ok in the tank, that the sensor prongs are clean and that the connection to the sensor is tight. Mine used to pop off every now and then and i had to trim the rubber sheath that fits over the connectors to make a snug fit after changing it.
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Re: Temp Light Flashing - Replace Relay 42

Post by Mocki »

Before you spend out on relay 42 / 43 , there is a simple check to do ( if you haven’t already )
We will assume the gauge is going to hot as soon as you turn the key on, when the engine is cold , and not because it’s really over heating ......
Take the plug off the thermostat housing ( I’m assuming it’s a late wbx here ) and the temp should go down to nothing . If this is so , it’s the sender at fault ( maybe even not a sender but a switch by previous mistake )
If taking the plug off the sender makes no difference , trace the loom, see if it’s melted where it goes near the zorst , or the insulation is damaged and it’s earthing out .
Next check the plug inside the black box in the engine bay and see it’s not corroded or damaged .

And again, up to the front where it owes out of the loom near the fuse box for damage or badness
Steve
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bertnuggit
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Re: Temp Light Flashing - Replace Relay 42

Post by bertnuggit »

Thanks for the advice...
Yes temp light flashes & gauge goes to max straight away and stays there, not due to overheating...Had a coolant leak, got corroded pipe replaced (shiny pipe shown on photo below), temp light started flashing after this & I've checked coolant levels since, garage reckon its not the sensors & more likely an electrical fault.
Afraid I don't know where the thermostat housing is, or the sender (temp sender circuit) or zorst! apologies for that, but I'll check my Haynes etc. Engine is a WBX 1986 I think, had the original engine replaced a few years ago.
Because I'm pretty clueless I was looking for some simple tasks to try first, like removing the relay 42, checking connections. I'll check the prongs, black box.
A few new faults point to electrics, can't get washer pump working & keep blowing the fuse, also the horn.

Thanks again, I'll read through your advice & have a go...
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bertnuggit
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Re: Temp Light Flashing - Replace Relay 42

Post by bertnuggit »

Apologies...ZORST....Exhaust! stupid me..........
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Re: Temp Light Flashing - Replace Relay 42

Post by Mocki »

Ok, my apologies, "zorst" common laziness here , yes of course, exhaust .

Ok, the thermostat housing is the plastic part at the end of the shiner new pipe someone fitted for you ( I’ve marked it in red on your picture ) it has two ports, one for the temperature sender, one for the thermostat switch for the carb heater , the carb heater is the one easiest to get to from the angle the picture is taken, facing the wheel , the temp sender is round the other side, facing the front end of the van , it is possible they have damaged the wire , or possibly mixed up the connections ,
If you keep the engine running for about 15 mins , the carb heater should switch off , does the gauge go back down at this point ?

Image


Another thing I notice from your picture, you have early air intake filter box , yet the rest of the van appear to be a early late , and that you have or appears from the picture to have a hose clamp missing off the air filter .
Also the petrol pipes look like they need a close inspection .
You have a 2.1 water pump with the extra spigot blanked off with a stubby pipe , watch it doesn’t fail !
Steve
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Re: Temp Light Flashing - Replace Relay 42

Post by bertnuggit »

Thanks Mocki, the temp gauge goes to max temp & stays there.
I'll have a look at the thermostat ports, you mean external wires? I'll check connections...
I had the engine replaced as old one had poor compression, the replacement engine was younger, garage probably used some parts from old engine.
I will look at air filter to fit a hose clamp.
Yes the water pump was replaced by RAC when van broke down a couple of years ago, they fitted the blanked off pipe as the new water pump was different, I do check that stays tight!
Impressed with your eagle eyes! what looks wrong with the petrol pipes? I have had some running problems & backfiring, got new fuel filters & assumed it was crud in the fuel if I drive with a nearly empty fuel tank?
Plenty for me to look at........
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Re: Temp Light Flashing - Replace Relay 42 - FIXED?!

Post by bertnuggit »

I had a fiddle about this afternoon, I cleaned some contacts including one the black box, checked the wires around the thermostat & tidied them up, noticed the connector to the top of the expansion tank wasn't firmly attached to tried to get this to connect better. Started up the van & after the initial temp light flashing it stopped & didn't reappear!!

Isn't a 42 or 43 relay near the front fuse box, think there was a 21, I'll have to look again & take a photo!

So onto the next job, getting the windscreen pump working...had a real job trying to attach the hose to the new pump, put it all back together & nothing, apart from blowing fuse 10...
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Re: Temp Light Flashing - Replace Relay 42 - FIXED?!

Post by Mocki »

Relay 42/43 isn’t in the fuse box, it’s up behind it , higher , above the Earth crown ,
Steve
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bertnuggit
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Re: Temp Light Flashing - Replace Relay 42 - FIXED?!

Post by bertnuggit »

Ah yes, I spotted some relays higher up above the earth crown this afternoon..

Luckily the temp light problem seems sorted now, I think it might have been the packard connector on the top of the coolant tank, I plan to fit a new to get a better connection.
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Re: Temp Light Flashing - Replace Relay 42 - FIXED?!

Post by jrt »

bertnuggit wrote:Ah yes, I spotted some relays higher up above the earth crown this afternoon..

Luckily the temp light problem seems sorted now, I think it might have been the packard connector on the top of the coolant tank, I plan to fit a new to get a better connection.
That was my problem as i said earlier...although my problems only started when got a new sensor and the connection wasn't as snug :roll: .
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Re: Temp Light Flashing - Replace Relay 42 - FIXED?!

Post by bertnuggit »

Yep, Thanks David, I hadn't realised where you meant when I first read through the responses....I cleaned various connections then found the sensor connection wasn't great, I fiddled with it to get a better connection which seemed to make the difference! I'm glad it turned out to be an easy fix because my skills are very limited..

Thanks again for your help, I'm now onto the next challenge of trying to get the windscreen washer working....
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Re: Temp Light Flashing - Replace Relay 42 - FIXED?!

Post by Stesaw »

That van looks familiar :lol: .

For some rather delayed closure on this. For anyone else chasing similar issues.

There was also a duff relay 42, as this is now my van. The temp light was fixed by PO, but the fan never kicked in. After grabbing the multi meter and checking the rad connector nothing was happening so swaped the 42 relay and fan kicked in.
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