Rats nest

[Matt Elan]

So here we go again. Went to take the ‘working’ plus 2 out. And the rear left indicator isn’t working. Chased the problem down to somewhere in the loom but only after pulling out half the interior and loosening off the dash. Lying in the car with my head in the passenger footwell I was not too impressed to see a chocolate block connector stuck to the heater box, random loose wires hanging down and various cut off wires, some of which appeared to be live.

So I'm biting the bullet (literally in some cases with he state of some connections ) and with some reluctance have ordered a set of new looms and will be rewiring the car in the next week or so.
I'm a bit worried about the non standard fuse box and the fact that the rear loom seems to be stuck under the glued down carpets, so its not going to be easy. But its better than chasing bl****y electrical issues, which always emerge after fixing other ones on this car.
Watch this space.......

[mikealdren]

Good luck. I'm planning the wiring for my Zetec car and I'm thinking of making my own harness (the project is part of the fun) because I am re-thinking the use of relays etc. and obviously the engine harness is quite different.

Keep us posted on how you get on.

Mike

[TBG]

Matt - you are very brave..................

[Andy8421]

So here we go again. Went to take the ‘working’ plus 2 out. And the rear left indicator isn’t working. Chased the problem down to somewhere in the loom but only after pulling out half the interior and loosening off the dash. Lying in the car with my head in the passenger footwell I was not too impressed to see a chocolate block connector stuck to the heater box, random loose wires hanging down and various cut off wires, some of which appeared to be live.

under dash IMG_2727.jpg

So I'm biting the bullet (literally in some cases with he state of some connections ) and with some reluctance have ordered a set of new looms and will be rewiring the car in the next week or so.
I'm a bit worried about the non standard fuse box and the fact that the rear loom seems to be stuck under the glued down carpets, so its not going to be easy. But its better than chasing bl****y electrical issues, which always emerge after fixing other ones on this car.
Watch this space.......

Looks fairly typical. You are however missing the obligatory burnt out wire taped up with insulation tape, and (for an S4 / Sprint), the melted white multi-way plug and socket where the loom goes through the bulkhead.

[pharriso]

Looks fairly typical............. and (for an S4 / Sprint), the melted white multi-way plug and socket where the loom goes through the bulkhead.

So true!

[jono]

OP,

If it's not too late see if you can get your dash loom made up with flag connectors - much easier to fit without crushing all the wires up against the heater box when you fit the dash.

I went through this and bit the bullet and changed them myself on a new loom. I honestly could not see how it could have fitted safely with the original straight connectors on - it was so tight! (after and before shown below)

[Andy8421]

That is a very impressive job. Shame they didn't all come from the factory like that.

Seeing the amount of wiring on what is a small, relatively simple, 60 year old design, it does make sense that modern cars use a serial communication protocol between the various modules.

In principle, just 3 wires - power supply and two wires for the CAN data bus. Makes troubleshooting with a bulb and a bit of wire tricky though.

[Bits]

I'm doing mine (new loom) next month (Sept), with a 30 yr time served ex Bentley electrician, in my S4 Elan.

[Matt Elan]

Ordered the looms and have scanned in and blown up the Plus2 wiring diagram to help my ageing eyes! Not looking forwards to unglueing the carpets to get at the rear loom.

[tonyabacus]

Matt, take a look at the previous "Two wiring harness questions", I have just posted a response to John on how to get in and do that job on my S4FHC, also look a little earlier in same post.

I made the job easier by taking out the rear parcel shelf on my S4 FHC to thread the cable through that tight corner above the wheel arch. I suspect you may have to do something similar if you have a +2 as the harness has a link under the front edge of the parcel shelf taking the courtesy light and heated rear screen cables across to the other side. Depending on whether the harness has been out before you may or may not have to pull the shelf to get at the old cable.
Tony

[Matt Elan]

Thanks for the encouragement. My Plus 2 was restored some 20-30 years ago when it got a plus2s interior so wiring loom siting down the back isn’t obvious. The carpets and sound deadening felt is firmly glued - even in the boot - in place just to make my life harder! It’s going to be fun (ish) I suspect.......

[Bigbaldybloke]

I rewired my early Plus 2 recently. The rear harness is the original standard one with just connectors replaced as necessary. The dashboard one is a lightly modified original, to incorporate a voltmeter instead of an ammeter and an electric oil pressure gauge and a couple of other tweaks. The front harness is a complete custom made one I made from scratch to incorporate additional fuses, relays, electric fans, electric headlight pod motors etc.
Really chuffed, everything worked first time, no sparks or smoke or even blown fuses. It was pretty straightforward, I bought a load of wire of all the different standard colours as per the original and a selection of good quality crimping tools, heat shrink, clips etc. The only messy area is behind the glove box where the three harnesses interconnect, the bonus I had was that all the interior trim was out so I didn’t have to try to get wiring behind carpets and trim.

[mikealdren]

Hi BBB,
do you still have the list of wire that you ordered to give me an idea of lengths and gauges required?

thanks
Mike

[Bigbaldybloke]

Mike, will check out what and who I got it from, basically a seller on eBay was selling bundles of wire, 10 lengths, choose your colour, am out racing radio control cars but will get back to you this evening. Bought several bundles.

Simon

[mikealdren]

Hi Simon,
yes that sounds the idea, I'm just at the stage of trying to decide roughly what lengths I need (lots of black and purple!).

I'm basically going for the Lotus colours supplemented by some UK std colours for new applications. I'm planning to use more relays so I may use lighter gauges in some cases behind the dash. I definitely want to improve on the original Lotus standards and I was impressed by Jono's work, it's set me a target....

There's no time pressure for me.