Flashing Coolant LED

[Robsey]

Looking at Burtybassetts vehicle, then that 'should' be the early wiring format with 12 torpedo fuses in the fuse box.

Not the crazy multitude of connectors as found on the later CE1 (central electrics) fuse box.

The principle of the gauges, the senders and switches should be the same.

Where yours differs, is that the shortage indicator relay-thingy (No 43 or 42) is mounted on it's own little relay socket on the A pillar close to the earth crowns.

Also the pin number on the instrument ribbon connection may be different, but the wire colours are the same.
VW buggered about with wiring order and pin numbers a couple of times during the T3 production run.

I recal Italjhon had a few pin anomolies on his late series van.
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Finally - all these vans are running on very old wiring that at best has been left alone, but has deteriorated with age and ambient environment effects (engine bay heat and atmospheric moisture).

At worst, a previous owner may have buggered about making poorly judged repairs, bodges or in their minds, upgrades.
That plus age and deterioration means you have plenty to think about.
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The reason why I said you 'should' have early torpedo 'euro' fuses, is because some people retro-fitted the later wiring format.

I hang my head in shame, because I am one such person.
I converted the van to the CE1 fusebox and wiring.
I spent days going through used van looms from a 1987 van, looking at every wire, and I changed well over fifty lucar (spade) connector terminals, ring terminals and even the bullet terminals in the CE1 plugs.

I hang my head in shame because the torpedo fuse box is very dated, but very simple, and doesn't bugger-about zig-zagging wires back and forth un-necessarily.

I did this thinking modern was better.
I now think that I shouldn't have fixed what wasn't broke.

On the up-side.
If I hadn't done the conversion, I wouldn't have researched the wiring, and I wouldn't have written all my fuse box threads.

[Burtybassett]

This is my fusebox - with Spade Fuses.
It's a 1983 North American Westfalia Vanagon....don't know if this has any bearing on anything but might differ from the Euro vans.

[Robsey]

That is perfect.
All the terminal references that I sent are correct for your van.
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I was looking up the simple layout of the UK 1983 van, just in case.

For those that do have an early UK / Euro spec van.
This is the diagram.

[Smiffo]

OK. Progress….

Wiring looks OK apart from  what looks to be over 100k resistance to earth from pin 3 of relay 43/42 position 3 in fuse box.
That looks a little high for coolant level sensor?

Will check that in engine bay later. 

Continuity through the rest looks to be as it should though.

Low point - LED started flashing again on way home from camping last weekend despite relay 43/42 being removed. I think SB was right. Capacitor issue or something at dash end. To make matters worse - the dash pod is hanging together with bits of tape lol.

 

[Smiffo]

I think I am there. SB was right above in the chain. Capacitor or similar in the temp gauge itself.

Spotted new dash on ebay, has a ( non-working ) LCD in it which I may or may not fix with the brickwerks kit at some point, and all the plastic was in place with good ribbon including BOD circuit.
Rev counter with working temp and fuel gauge included too. ( even had a little video of LED test sequence lol )

Easy swap out and has been working fine since.
A few more days I will pop the relay 43/42 back into position 3 and see if the circa 100k resistance on low coolant circuit is OK.

If nothing else, I can retire my cracked old dash with complimentary duct tape holding it together, to a test bed.
When winter comes the plan is to replicate the fault and hone my soldering skills. 


 

[Smiffo]

Ok, 

All seems good. Time to pop the relay 43 back in and see what happens.

[Smiffo]

Hmmmm.

Need to think this one through a little.

So far LED and gauge work as should, even with relay 43 in.
I have even done the test to short across pins 4 and 6 where relay goes, and that drives needle to hot and LED flashes instantly.


Things to note:

1. When I remove that short, needle returns to normal and LED stops flashing instantly - I read somewhere you should need to turn off ignition to stop the flashing.

2. With relay 43 in, it’s all good except when I disconnect level sensor in the engine bay, and the LED does nothing.

3. Tested for short to earth on pin in relay position that goes to sensor. No short exists. When plug level sensor back in, I have somewhere around 70k resistance to earth. Seems good.

4. Solid voltage on 12v supply to relay position with key on.

5. Earth for relay position good. ( Negligible resistance. )


Have another relay 43. Behaves exactly the same…..
The niggling doubt in my head at the moment is not needing to turn off the ignition to reset the flashing LED once the short is removed.

Is it the gauge that needs resetting by turning off ignition, or the relay?

Once I know exactly how it should behave, I know what’s wrong.