Bessacarr - Fiat loom connection

[Markd]

I have a 2004 Bessacarr E745 and I've just twiggef that neither of my rear fog lights work - even though they are part if MoT I'm not sure they ever have whilst I've had it!
The bulbs are good, there's no power at the back and low resistance between fog light and other light earths. All the other lights work fine and bright.
The fuse is good and I can hear the relay behind the switch kick in when I put it in.
There must be a discontinuity somewhere. Could be a wire broken of course but a quick check along the chassis didn't reveal anything obvious.
My next thought is that the connection between Fiat cab loom and Bessacarr body loom should be checked so I can confirm that power is at least getting that far.
For the life of me I can't find it - the Bessacarr loom seems to go into the rhs cab rear chassis section and i can't see where it emerges.
Does anyone know where it goes or where the connector(s) is/are please?

 

[in h]

The most likely place for a fault is a connection at the switch or the relay, but I guess you checked there.
What happens if you apply +12v to one of the rear fog lamp connections. Do they both light?
The way to trace an unknown break is to use one of the RF signal generators that let you track where the voltage is getting to, but if you don't have one..

[Later] Don't overlook the obvious. Check the fuse is good and not corroded.

 

[Markd]

I've taken the switch panel out and there's dozens of wires going to the connectors!
Can't understand quite why but guessing that they use a standard loom that can serve all specifications. I only have 3 switches - one is for rear screen heater which of course isn't fitted there are 2 spare.
The fuse is good - tested it and it triggers the relay when inserted.
Cant get at relays as they are inside switch housing.
I've found a wiring diagram on the web and identified wire colours. I think I may have seen them when I tidied some loose wires in engine bay today.
They may have been pulled about when AS did the air suspension last autumn..
I haven't checked the rear cross connection yet - good idea.
I can see the multiplug connector from rear of loom to light clusters but I'll have to take rear panel off to get at it and I've already found that nuts aren't captive and it's a two person job to hold them and use screwdriver to turn bolt

I don't have RF tracing kit. But I'm optimistic that it will be, as you say, a pulled connection one end of the wires I saw and disregarded earlier. They looked like a pair of loudspeaker wires - may yet turn out that way too now I think about it!
Anyway thanks for the suggestions.
Thankfully my MoT man didn't look at the rear fog yesterday so I've got a year to sort it

 

[Markd]

One step forward - two steps back!
There is power coming out of the panel so switch and relay are good.
The two wires are unfortunately speaker leads for rear of habitation - but when someone took the speakers out they it the leads 20mm from the roof where they are solidly fixed
Unbelievable really as there's trunking in the cupboard with wires to spotlights - could have been left full length.
So if I ever want rear speakers I'm going to have to be very careful stripping the wire
More rummaging under dash board coming up.
Ca t help but think fiat provided terminals for rear lights when they made these camping cabs - just got to find them!

 

[Markd]

Well they're working but I've no idea what the specific problem was
Wrestled with the dash etc to check connectors and found what I think was the last before it went down the wheel arch under carpet and step lining into chassis(?)
Power on correct coloured wire but still no lights.
Went to rear and pulled big bundle of wires up into cavity to relief a bit of strain - both lights fire up!!
Messed around with wires again trying to find the problem but couldn't get them to go off!
Which is sort of good but means they could fail any time I suppose.
I suspect a loose connection at the connector block inside the bumper and I may yet take the bumper off and play with it.
Doing so will enable me to remove the towbar electrics which I no longer need.
I took the opportunity to replace the 5w tail bulbs with the specified 10w which should help generally and will be slightly better if the dogs drop out again when I need them.
Also replaced a couple of darkened 21w bulbs - may as well because getting these old Bessacarr light towers off is a pain with the 'plugged hole' fixings taking an age to release.
I've modified them so I have a small cap with a thin rim that I can lever off rather than dig out and chew up the plugs.
I did move the wires around at the rear but if I'd jiggled them a bit more in the first place I could well have saved a days work

 

[in h]

Splendid news!
I was a bit naughty and fitted LED bulbs in mine a few years ago (not the indicators - that's too tricky) and so far they have been fine.
To be quite honest, the rear fog lights only get turned on once a year, at MOT time. Last time it took me a while to remember where the switch was. [Note to self: it's next to the mirror heater switch]

 

[Markd]

Nothing too naughty about leds.
I recently swapped 10 for the side 3@ and high level front-rear @2 so if I ever park on highway (theoretically laybayl) have saved probably 4 amps current - overnight this might mean the van will start in the morning!
I read recently (here?) about someone putting 10w leds in reversing lamps so he could actually see where he was going. I rather think that in these small diameter old Bessacarr lights it wouldn't make that much difference.
I'm not too worried about the consumption of lights used whilst running and ad I don't do massive mileage at night I'm not sure that I'm going to burn out that many bulbs.
Maybe brake lights I suppose - but I've got a lifetime supply of old 21w bulbs on the garage.
Especially now modern cars have gone capless!!
Like you I don't use fog lights that often - in my case not even at MoT

 

[in h]

It wasn't to save power: it was for longevity. Replacing the rear lenses is a pain on my van.

 

[Markd]

I agree with the longer life - the high level position lights on my van are a pain to do as are all the skirt lights on the side so putting leds in had the added benefit of never having to do them again.
Now I've changed the caps on my rear lights access isn't too bad - I don't understand why Bessacarr 'sealed' the tail light fixings.
Any access marked the plugs permanently and as far as I know you couldn't get replacements.

 

[Markd]

Talking of leds - I noticed that a lot if the MoT testers manual now refers to light sources of any sort without reference to power.