Starting to dig through issues on an 84 mk2 GL and having some fun with the temperature sensor / clocks. I believe the car is running CE1 and has had replacement clocks at some point. Odometer works sometimes, digital clock is blank (but not bled out) and temp gauge looks concerningly hot (about 5/6 when up to temp) but pretty sure that the engine isn't overheating. Fan kicks in occasionally and it's not steaming it's head off. Fuel gauge seems to function correctly. Voltage reg puts out 9.8v when engine running. Part number on the clocks is 191919535. There's what looks like a date code of 12/85 on the back of the speedo module. Rev counter has VDO logo. I have a spare set of clocks from what I think is a slightly later car - part number of 191919035 and date code of 7/89. Rev counter has MOTOMETER logo. After swapping the clocks the coolant light (above temp sensor) is flashing fast and constantly. This seems to be coolant level warning? I'm hoping this is the problem as: Newer clocks expecting coolant level sensor Car doesn't have the sensor (early expansion bottle) Hoping I can add a short/jumper wire or resistor to stop the flashing warning light. But not sure where to do this. There's a couple of connectors in the engine bay near the expansion tank but not sure if either are for the coolant level, especially as the car never had one. I've been looking at pinouts for the black and white connectors that go to the clocks but can't find anything obvious that relates to the coolant level warning light. Any tips, pointers or help much appreciated!
the coolant level warning only works if you have a 42/43 relay, the bad news for you is it taps into the coolant temp sensor wiring so this isn't your issue. even if the car was factory fitted with level warning, simply pulling the relay disables the system and the clocks carry on as normal from your symptoms I'd start by checking the cluster earth, its the brown wire on the white plug, for poverty spec cars this runs to the claw above the fusebox. check the main 4 way white earth spade block in the headlight loom, this should have a wire from engine loom, dash loom and sometimes rear loom into the front of it then out the back is another wire which goes off to the claw providing the earth for it
Hey up Jonny, Brown wire on white cluster plug (pin 5 on long side) has good continuity to the earth claw above fuse box. They both have good continuity to chassis. I have to say you've lost me a bit on "main 4 way white earth spade block in the headlight loom" - any tips on where to find that? Couple of photos of the horror that is the fusebox and surrounding wiring ;') Cheers!
dont see anything obvious aside from all the bodgery on the headlight loom this should be hanging out with it fuel pump doesnt apply to you obv, but there may be a brown from the fuel level sender to it or it'll be popped into the claw either way thats fine
Found it! It's a little less white than the one in your photo though heh. It's got a full complement of brown wires and good continuity to the claw. Soo... am I right in thinking that the newer clocks are going to be unsuitable / not easy to stop the flashing red coolant light? I don't really want to remove it from the gauge and lose the 'too hot!' warning. And yeah, plenty of horrid bodges tucked away in there!
all the earth must have leaked out and stained the housing seems good there, looks like the cluster is just faulty if it has the same style of temp gauge you can try swapping that over
one thing to try, disconnect the yellow/red wire from your dash temp. does the light still flash? My mate had similar issue with his the light would flash but temps were normal. after much messing about what it turned out to be was a faulty temp sensor. all i can assume was it was intermittently shorting internally to earth, enough to trigger overheat warning but not enough to actually affect the gauge temp display
Have you got a picture of your clocks? If you're lucky you might be able to get just the temp gauge from VW Classic, or even used on ebay. I have repaired the temperature gauges before, take the face off, remove the board, new capacitor and you're away. The rivetted gauges are a lot harder than the ones where the face is just "crimped" on. Flux and some good solder wick/solder sucker are required if you're going to attempt.
Update on this - had a bit of time over the weekend. I noticed the speedo modules were different - with the earlier one having a row on pins in the back and the later one without - so swapped back to the old one in case that affected the low coolant warning light. It didn't. Interesting that there's more going on in the older speedo though - a PCB and some funky looking components. Next I thought some more about the flashing LED - there must be something doing the flashing and there's no silicon / chips on the main flex PCB apart from the voltage regulator. Peeking inside the temperature sensor module reveals a small circuit board with IC and some other components. So I swapped the temperature sensors - easy enough to separate from the white plastic part with some gentle leverage. Not the best photo but it's in there somewhere. @NateS2 I hadn't seen your comment about the cap on the board - thanks for input and I might test the cap in the newer gauge to see if it's failed. It's one of the riveted on types though so might not get around to it for a while heh. Not run the engine up to temp yet but assuming it will still read high but I can live with that... for now at least Gauge circled in red is the one that works in my CE1 84 GL. Interesting that it says 124 degs C on it, but no rating on the newer one. Makes me wonder if there are different temperature sensors that are rated to work with different gauges, as the signal to the gauge is only varying voltage? @rubjonny I didn't try disconnecting the red/yellow wire so can't report back on that but might try if I get time with the other gauge/clocks. Oh and in case others are having issue with alternator / batt warning light - I found out that on my car the warning light stays illuminated until I blip the throttle after starting. If I just start the car without any pedal action it stays lit. Might save you some hassle knowing that!
the board you swapped over is for the oil pressure warning system, both would have had it just the other one has had the board pinched out of it for some reason all mk2 golf temp gauges are the same rating and use the same spec sensor, just different designs. the sensor just adjusts the resistance to ground if you disconnect the yellow/red wire gauge should stay at 0 and no light, but yeah its probably just the gauge that's gone faulty yeah some alternators need a blip[ of the throttle to start working, when new you wouldn't need to but age catches up with us all so long as its putting out 13v+ when light goes off and you put some load on by turning on the headlights you're good
Right so the speedo from 1989 in photo above has had the pcb removed? Goes to show that there's always surprises lurking! Yep alternator putting out ~14v and happy with headlights / heater on etc - and plenty of length on the brushes. Hoping that's the issue solved for now. Cheers
yeah the boards or switches can fail so the obvious solution is bin the warning board. no lights, no problem
