Ghost voltage at fuel pump ?

[Durango2k]

Hi guys,

There are not many leads on the RHD side of my wiring loom.

2 of them are a bit thicker, cloth outsides, and end at the fuel pump.

One of them becomes 12V when I switch the ignition on. Fine, I thought, thats the fuel pump source.

Sadly, the old pump does not make a single noise on these two wires.

It does a nice wrrrrr and pumps on the battery (I overhauled the pump).

So, the 12 V on the rear are some kind of "ghost voltage".

I then went in front of the passenger seat, to test their sources. However, there's ghost voltage as well: none of the cables there (with a correct earthing of the pump of course) is able to drive my pump.

What next ?

I'll upload a picture of the multi-connector situation in the passenger footwell, maybe someone can show me what to put where ?

At least, I made the washer to work today- I found one more open connection, it was green-black below the glovebox.

Carsten

Here's the pic:



The three on the left which I bent a bit away (2x twin connectors and the purple-white ones) have a 12 V supply when ign is switched on. What I managed to identify is what I have connected, the open wires are all "unknown". The halfway-stuck-in is the one which only gave me ghost voltage for the pump.

[cactusman]

Best bet would be to refer to a wiring diagram although the wires that join in the passenger foot well should just join colour to colour. I would turn the ignition on and use a small bulb at the connection in the boot . Test from the live wire to a ground point in the boot. Dnt use the ground wire to the connector. If the bulb lights then the issue is the ground wire to the connection in the boot.

[Durango2k]

In fact there are 3 looms meeting there:

From the left, seen between my left (index?) finger and the thumb. This is the source loom.

From the from right, there's another loom.

And to the right, 4 wires to the rear end. This already IS tricky because the wiring plan says that both rear light clusters are sourced fully individual, minus the license plate lights.

So, the RHD loom should have
- indicators: greenwhite: yes
- stop light ?
- standard rear light ?
- fuel pump including an earth eye connector (present but ghost voltage).

Thats 4 wires only, too few if sourced individually.

It seems that I will source standard and maybe brake lights from the left, there are extensions present.

Furthermore, strange, the left loom has many more wires, for example two ending at the fuel filler hose which never became 12 V either whatever I try.

Carsten

[christopher storey]

There is really no such thing as "ghost voltage" ( although there can be " ghost current" - my invented phrase -see 2 below ). If the wire is giving 12 volts when tested to earth , it is giving 12 volts when connected to the pump . If the pump does not then work there are 3 possibilities :

1. The pump is not earthed - this I regard as the most likely and can be eliminated by providing a separate earth to the pump and seeing whether this makes a difference

2. The wire is passing 12 volts , but will not pass anything other than minimal current . The probable cause of this would be broken strands within the wiring causing very high resistance and can be checked with an ohmmeter. This is something which in my experience can happen with old wiring although it is not that common

3.The pump has failed between bench testing and installation


Good luck with it

[christopher storey]

As far as your wires are concerned, you should have

RH Tail lamp Red

RH Indicator Green/White

LH Indicator Green/Red

LH tail lamp Red

Both brake lights Green/purple

Reverse light Green/Brown

Number Plate lamps Red

Fuel Pump White ( although shown as White/Purple on some diagrams )

Interior Light ( above hatchback ) Purple /Green


I hope this helps

[Durango2k]

Hi Chris,

Thanks for the list.

As you can see, Mr. Whittaker saved a wire. The wiring loom from the rear of the car just shows 4 wires.

They should be:

- indicator green/white, yes
- tail light, red, source: yes, but only 4 wires and no red one. So this was sourced from LH side, despite the wiring plan says otherwise !
- fuel pump ? White thick cloth wire
- stop light - green/purple one as per wiring plan.

Which leaves me with one more or less cloth wire, the one which I now connected to the red one for the moment, but have no idea what it should do. Maybe it was for the RH wing aerial which is not there on this tub but was there on my old tub ?

I'll try the fuel pump with a better earth, next.

And am happy for any small progress- my repaired light switch now does not make any arcing sounds, and the loose feeling is a bit better, because it still is a bit loose/worn, but it does not wiggle the power throughput, I mean it does not flicker if I wobble it a bit.

Carsten

[Heuer]

Are you sure you are not trying to connect the pump to the fuel gauge? It has 12v on it and then goes via the tank sender resistor to earth,

[andrewh]

I agree with Christopher, but really its pretty easy wiring up the back there. You have purple ( from memory) which is the interior light, and then the rear light feeds which run down each sill, so on the LHS just the feed for the LH rear lights and the number plate light. These should be identifiable by a simple continuity test with the light switched on, then you have the fuel gauge and the feed to the fuel pump. I would take a known good feed from a spare battery and try the pump in situ with it connected to its own earth. If that doesn't work provide a good earth back to the battery. If that all works, and your loom feed doesn't work then you have a dicky wire on feed or earth. Good luck.

EDIT. having re read you original post you refer to the RHS. The power for the fuel pump comes down the LHS regardless of which side the car is LHD or RHD, but I am sure you know that, just wondered why you referred to it as the RHS loom

[Heuer]

Green/Black is the tank sender which controls the fuel gauge. Do NOT try connecting it to the fuel pump.

[Durango2k]

Found a few more things:

- heated rear screen now works (thick single black on left side loom)

- fuel pump now works, when I use the RH loom and the wires on the front becoming "live" when switching on ignition. Which wire on the left should it be ? The thick long cloth white one ? This could easily be lengthened to go all way to the the pump. This would free one wire on the RH side, for main lights for example, which I would else have bridged over. Only problem, see below, is, that exactly this white cloth wire delivers a solid 1.9 volts. Broken I believe, because even fed with 12 nothing more arrives. And its not the coupling, and its behind the bench.

- interior light too has a broken wire. Purple and green, 12 V before rear bench, some volts after it, but no lamp. Wired to the heated screen it works. Hm.

Now, how do I repair this part of the loom ? Disconnect anything an the rear end, put it up together with a rope, pull out, repair and pull back through ? Seems impossible to get to the inner upper wheelarch ???

- R gearbox selection works, backwards driving centre light is fine.


Carsten

[Durango2k]

Lots more solved- rear lights now fine, may have been dead battery ?
Strange, today it simply worked.

Interior lights now fine: two reasons: did not bolt-on the rear earthing point, it did not like that, and even better, the fuse was a bit corroded on one side. After cleaning I had the same 12.5 Volts on the rear end- but this time it had enough oomph to drive the lights. Success !

Next job: get the door switches to work, there are no wires present (on my 2+2 I can grab behind the switch !), and find out what the ruptured remains of purple and purple-white mean.

Then, get the stop lights to work, and find out more about the horns and the
Engine fan. And why the handbrake warning light works nicely, whilst the empty brake fluid reservoirs show nothing.

Near the finishing line....

Carsten