Club 80-90 Forums

Thanks guys. I’m hoping to get back to it tomorrow evening so will report back.


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You can't miss it.

Some photos of my trouble-shooting so far.



The main thing I found is that for the D15 feed to coil, the voltage starts off at about 8V when the ignition is switched on and slowly drops to about 2-3V.

It looks as if someone has taken a feed from the black D15 feeder wire at the T1a connection in the Engine Bay junction box. This feed runs back to a two-wired unit on the gearbox shown in the next photo. I'm not sure what this unit does (E D I T: maybe the reversing light switch?) but one of the wires was broken at the spade so it's not doing anything currently. The wire back from the unit splits again in the Engine Bay junction box and the wires appear to go to the back LH and RH lights.



At the ignition I have a small black wire that goes live when I turn the key but it seems to run to Pin 9 of the 14 Pin connector that connects to the dash console.

Any thoughts or ideas would be appreciated. My next move is to try to remove the dash and try to trace the coil wire back from the ignition switch to the Engine Bay junction box.

Which of the connectors are you testing for voltage ?

You should disconnect the connector block when testing voltage so there is no chance of a backfeed

The spade near the gearbox is the reversing light switch

Hi Carrera. I disconnected T1A connector in the Engine Bay junction box and measured the voltage coming from the front of the van that would normally feed the coil (and in my case the reversing lights).

Which one are you identifying as the T1a connector ?

937carrera wrote:Which one are you identifying as the T1a connector ?

It’s the one shown here



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Well, that looks like the correct one, the loop off should go to the thermoswitch F35 - this is called T1c in the later wiring diagram in the DG wiring diagrams from syncrosport

It sounds to me like there is a broken wire, which passes some voltage, then as it heats up it goes higher resistance and the voltage drops.

Trace back to the fusebox and test the voltage there and also continuity from the fusebox to the connector

Will try that. Thanks Carrera.

Yours is correct for early vans, the reverse lights come off the connector and through that inline fuse to the reverse light switch on the gearbox.
Just to confirm you have the early type fusebox with bullet fuses?
Did you check the voltage with T1 disconnected? If the voltage from the fuse box was still low, then the problem is between the connector and the fuse box.
And DON'T leave the ignition switched on for any length of time while you are checking it could burn the loom out.

Thanks bigherb, since I have not seen any wiring diagrams with this reversing lights arrangement I assumed it was a fix that was added some time since the van was built. It's good to know this is the design. It would be great to have a wiring diagram for an early van but I have not been able to find one. It would be good also to understand how the coil is fed from the ignition. As I shown in the above photos, the only black wire from the ignition currently runs into the 14-pin connector into the dash console.

Yes, I checked the voltage with T1a disconnected so the fault appears to be somewhere between the ignition and the Engine Bay J-box. When I saw the voltage dropping gradually and consistently, I assumed that I was discharging a capacitor connected to the circuit. I had not considered that it might be a broken wire passing voltage with the voltage dropping as it heated up as Carrera described.

Good point on having the ignition off whilst tracing wires. I had not considered the loom fire risk.

What fusebox have you got bullet or blade fuses?

bigherb wrote:What fusebox have you got bullet or blade fuses?

Early-style bullet fuses.

Here's a photo of the back of the relay and fuse board. I didn't take a photo of the fuses but I checked them and they seem to all be intact.

The coil supply is not fused

There is a connection from the ignition switch direct to the fusebox, described as terminal 15. The feed then goes to the rear of the van where there is the spur for the reversing lights, which is then fused.

I don't know which fusebox connections are used - no wiring diagram to read, pretty sure you need to be looking for black wires

Hope that helps