temp gauge issue

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Brismike
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temp gauge issue

Post by Brismike »

hi got a 1.9 watercooled on a 86 temp gauge has never worked so bridged at the thermostate but got nothing so replaced the clocks now bridged gauge again and gauge went up, thought great sorted but no still nothing so replace the sensor on thermosate housing but still nothing, could have swore would have sorted and now puzzled what else can it be where should i look? thanks guys/girls 

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maxstu
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Re: temp gauge issue

Post by maxstu »

I suggest checking the multiplug that pushes on to bottom of clocks. Then wire resistance between sensor and correct pin in multiplug.
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AngeloEvs
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Re: temp gauge issue

Post by AngeloEvs »

If the temperature gauge is functioning when you bridge the gauge then, as advised, remove the dash, you can then remove the multiconnector shroud by unclipping it and inspect the condition of the edge connector. If ok, Locate the yellow/red cable and brown cable in the multiconnector and using multimeter probes measure the resistance across those two wires. Depending on the temperature of the coolant you should get a reading 1000 ohms or below but if the reading is much higher then you have a break in the wiring to the sender, poor connections or the sender is faulty.
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ScienceBoy
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Re: temp gauge issue

Post by ScienceBoy »

I’ve got same issue after bad mechanic (supposedly Vw specialised) monkeyed around with our dash. Now needle doesn’t come up. I think it did try for a while but no longer.

Where is the sensor?
Is it the sensor I ground or short to see if the gauge works?


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ScienceBoy
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Re: temp gauge issue

Post by ScienceBoy »

AngeloEvs wrote:If the temperature gauge is functioning when you bridge the gauge then, as advised, remove the dash, you can then remove the multiconnector shroud by unclipping it and inspect the condition of the edge connector. If ok, Locate the yellow/red cable and brown cable in the multiconnector and using multimeter probes measure the resistance across those two wires. Depending on the temperature of the coolant you should get a reading 1000 ohms or below but if the reading is much higher then you have a break in the wiring to the sender, poor connections or the sender is faulty.
The sensor is resistance based?


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AngeloEvs
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Re: temp gauge issue

Post by AngeloEvs »

ScienceBoy post. “The sensor is resistance based”

Yes. The Coolant temp Sensor on a post 1986 1.9DG is in the plastic thermostat housing. There are two and the one that you need to check is facing the front of the van. Wire colour code is yellow/red and brown with brown the chassis connection. If the temp gauge was working before the work was carried out then you should check the multiconnector at the dash is fitted correctly and if necessary remove the dash and make sure the copper tracks that the connector fits onto are not damaged.
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Brismike
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Re: temp gauge issue

Post by Brismike »

right still having issue want get sorted as weather is nice!!!! so temp gauge not going up how long does it take to go up as ive only ever done really small trips i would have thought it would go up and sit on between white line and half way which it dosnt it sits before white line. ive changed sensor got one from brickworks but im still thinking sensor as ive checked wiring with multi meter from multi pin by clocks to fuse/relay location and then from fuse box to sensor plug and all fine, ive bridged sensor plug and needle goes up so think thats saying clocks and wiring are good?? could i have got faulty new sensor or something else i should check recheck?. and thanks

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AngeloEvs
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Re: temp gauge issue

Post by AngeloEvs »

Where were you measuring at the fuse box, the only place is where module 43 or 42 is fitted and is best removed first?
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Brismike
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Re: temp gauge issue

Post by Brismike »

hi regarding checking the wiring all i did was put meter on one end to the other to check for any breaks sorry wasnt clear.

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AngeloEvs
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Re: temp gauge issue

Post by AngeloEvs »

With the engine at normal running temperature the resistance should be around 100 ohms and since you have replaced the sender with a new one my guess is you have a break in the circuit somewhere. The temp sender has a yellow/red wire that goes to the dash and a brown wire that goes to chassis earth and both of these have to be checked. Check the earth wire does connect to earth by following it through and doing a continuity test to a good chassis point.

The yellow/red wire goes to a black distribution box in the engine bay and from there to the dashboard multi connector via the rear of the module 43. From module 43 it connects to the dash via the 14 pin multiconnector to the ribbon cables. It’s a case of taking resistance readings at the sensor itself, then at the black box and then by inserting probes into the vacant sockets where module 43 would and use a meter to check that one of those connections actually connects to the temp gauge. I have pics of what to do regards testing via the vacant module 43 socket but I am away until the weekend.
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ScienceBoy
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Re: temp gauge issue

Post by ScienceBoy »

Brismike wrote: 14 Aug 2021, 14:46 I've bridged sensor plug and needle goes up so think thats saying clocks and wiring are good?? 
Doesn't this mean it's OK from the plug through to the gauge, indicating the sensor?
 
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Boneyt25
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Re: temp gauge issue

Post by Boneyt25 »

I have an issue with mine.

Proved adage and wiring by shorting the single yellow/ Red cable to ground. Gauge shot to max.

New sender ordered. So hopefully this will fix.

My question is...
Does this being faulty affect other things?
There's a separate sender for the inlet manifold heater. But just wondered as I'm also having a warm running issue , but might just be the carb. Ie. When engine up to temp, get kangaroo fuel and starts to stall on idle.

Boneyt25
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Re: temp gauge issue

Post by Boneyt25 »

Prb should have said. 1983 1.9dg. Was df
L. Water-cooled early

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