Red wire with white stripe to starter solenoid - what is it?

[JamesS]

Hi all,

I'm having some intermittent starting problems with my van and am just working through some of the excellent advice here - in particular on this thread:

https://club8090.co.uk/forum/viewtopic.p ... 8&start=15" onclick="window.open(this.href);return false;

However, I seem to have an extra wire going to my starter solenoid, and was wondering if anyone could tell me what it does, please?

As described on the Wiki, on my van there are two wires connected to the threaded bar on the solenoid: a thick one coming from the battery compartment and another fairly thick one going backwards (presumably towards the alternator). Then, as in Nicola&Tony's picture below, there's a thinner wire (red with a black stripe) going to a spade connector on the solenoid, but I also have a fourth wire (thinner still; red with a white stripe) which goes to a second spade connector on the solenoid.

1st stage: finding and removing the starter motor.

The second spade connector is visible in this picture (also from Nicola&Tony), but I haven't heard anyone mention the thin red and white wire yet.

2nd stage: opening the solenoid.

All of my starter motor/solenoid connections were clean, except for this thin red and white wire, which was badly corroded. I've cleaned it up, but have just discovered that the van (occasionally) starts even without it connected, so I'm a bit mystified as to what it does. Having connected my meter from the (disconnected) red/white wire to earth, I get 0V with the ignition off, 1.5V with the key in position 1 and 13.8V with the key in position 2 (once the engine has started).

Can anyone tell me what this wire does, please? It's seemingly not related to my intermittent starting problem, but perhaps once I understand what it does I'll be able to work out what to do next.

Thanks!

[luvmadub]

hi the wires you refer to are the ones that power the solonoid (the smaller round item on the starter) the wires go to the ignition switch. cant spell either.Rob

[itchyfeet]

The Spade on the solenoid is the trigger wire the large red/black comes from the ignition switch.

not sure what you mean by '13.8V with the key in position 2 (once the engine has started)' do you mean when cranking or when engine running?


Does the red/white look Origional or does it look alike an addition? Some people with corroded/ broken trigger wires add a relay somewhere triggered from the ignition switch and then this in turn powers the soleniod spade terminal but if this is the case it should only have voltage when engine is cranking.

Try following it and see where it goes?

[Mocki]

My guess is its either a secondary signal wire to try and solve the starting problem that existed before you owned it, or it's being used to send a signal to something else , maybe some sort of a
Alarm or immobiliser ?

Like has been said, try and trace it I'm pretty sure it's not original, I have certainly never seen one on any van .

[JamesS]

Interesting - thanks to all for the replies.

Most of the solenoid pictures that I've seen on the internet have two spade connectors (like the one above). Does anyone know what the second one is for, then, or are they just two spades onto a single electrical connection?

I'll try to trace it and see where it goes. I guess it must be a later addition, although it's been done surprisingly well compared to the other "later additions" on my van! It's threaded through the same tough, black insulation as the red/black wire (visible in the first picture in my original post), which is why I assumed it was original to begin with.

The red/black wire goes onto one of the spades on the solenoid and is definitely the feed from the ignition - if I remove that then, as expected, the solenoid doesn't work at all. The red/white wire seems to have no effect on the solenoid and is a puzzle...

not sure what you mean by '13.8V with the key in position 2 (once the engine has started)' do you mean when cranking or when engine running?

When the engine is running. The red and white wire attaches to the second spade on the solenoid and has a steady 13.8V to it once the engine's successfully started. Based on this I guess it must be something to do with the alternator, although it's certainly not the main battery charging feed as (1) I've identified this as being connected to the threaded bar on the solenoid and (2) the red/white wire is too thin to carry much current. Perhaps it's something to do with my split charge relay (?), though I'm at a loss to know what it's doing plugged into my solenoid if that's the case!

I'm going to try to get the starter off this weekend (assuming I'm skinny enough to get at it without ramps!), so hopefully all will become clear then.

Thanks again for the suggestions!

[itchyfeet]

You would not want 12V on the solenoid once running but DC and multimeters can lie to you, sometimes there can be a voltage in reverse direction through another device but no current available depending upon what it is connected to.

can you post a pic?

I suggest looking for red/white wires of the same diameer in the black engine box, fuse box area and dash area and see what they are connected to.

[JamesS]

Thanks itchyfeet, that sounds like good advice. I won't get chance to work on it again until Saturday, but I'll try to get a picture then.

It basically looks exactly like Nicola&Tony's photo (the first one in this thread), except that there's a thin red/white wire coming out next to the red/black one and connecting onto the second spade connector on the solenoid housing.

[One thing's that's just occurred to me that I should have mentioned earlier - my van's an automatic, in case that makes a difference.]

[itchyfeet]

Bentley shows an Aux battery cutout realy on Camper 86-89 auto box, extra red/black 1mm2 from the solenoid trigger wire?

[Mocki]

Argh!
Inhibitor switch !

May I suggest you insert the details of your van into your signature so anyone answering knows what van you have .
Also a location in your profile could mean someone a couple of miles away can p over and look ....

[itchyfeet]

I'm not too clued up on Auto's how does a connection to the solenoid inhibit starting?

[Mocki]

I'm not up on autos either, but I do know they have a inhibitor switch on the gear selector , which I assume needs a signal back ?
Reading in the fact the OP said the fourth wire was included in the VW loom and I have never seen a manual transmission with the fourth wire.
I maybe wrong, please prove me so, amd solve the OPs riddle !!!

[colinthefox]

On some split charge relays the coil is grounded through the starter solenoid. It seems a bit weird, but it ensures that the leisure battery doesn't share cranking amps with the starter battery, as it de-energises the split charge relay while cranking. That would be consistent with having volts on it with the engine running, but not operating the solenoid.

So if you can trace the wire to a relay, that could be it. I have no idea where your split charge relay me be, or even whther you have one at all, but worth a look.

Colin

[JamesS]

Sorry guys - location and van details now updated. Stupidly, it only occurred to me that the auto might be different once I started pricing replacement starter motors and saw the different types for auto and manual.

So it looks like the options are:

• 1. Auxiliary cut-out relay,
  2. Inhibitor switch or
  3. Something to do with the split charge relay.

My split charge relay is under the seat with my leisure battery, so that should be easy to check. I guess I can also try starting the van in "Neutral" rather than "Park" and test to see if the voltage to the wire is any different, or something along those lines. Having said that, the van does start without this wire connected, so I'm not sure how it would work as an inhibitor.

Thanks again for all the help. I'll let you know how I get on at the weekend (assuming it doesn't chuck it down too much!).

[Mocki]

It should start in both neutral and park, but shouldn't in "R" ,1,2 or 3
That's what the inhibitor is there for.....
Like I said I'm not familiar with the autos and I'm not sure who has a early auto , although I know of three or four late ones on here....

[itchyfeet]

looking at wiring diagrams in bentley the Auto gearbox inhibitor switch breaks the 6mm2 red black main trigger wire so it's unlikely to be related to that
Inhibitor switch could be the cause of poor starting if this switch is failing but corroded trigger wire or faulty ignition switch could also be culprits.

Looks to me like aux battery cutout realy which disconnects the second battery while cranking ( actually it connects when not cranking)

As described by colinthesherlockfox bentley shows this normally open realy realy powered from +V and it grounds via the solenoid coil ( which has a low resistance) when it's not cranking so it would have a voltage when engine running ( but there will be almost no current). When cranking the realy coil sees +V on both sides and it switches off opening the circuit.

shown as a 1mm black red in bentley but early van probably different colour.

Next challenge is to find the relay.