12 replies to this topic

[AVV IT]

Following an electrical disaster this afternoon, It looks like I'm going to have to replace the entire loom.

What's the best way of going about this though, is it better to start at the back of the car and work towards the front, or vice versa? I was planning on doing it systematically, by disconnecting the components from the old loom and reconnecting them to the new loom one at a time, or is there a better way?

Any other hints, tips, and advice would be greatly appreciated.

Ta Muchly

[robminibcy]

When I did mine I found it best to work inside out undoing and replacing plugs as I went. I found it to be a very enjoyable job and not had a electrical problem since, in my opinion it is something every restoration or rebuild should include. Depending what year and model yours is there might be spare wires which don't appear to go anywhere. My car is a 79 and doesn't have a foglight but the new loom did include the wires for one. I just tucked the wires under the dash.

[midridge2]

Depending on year, some run behind the cant rail and some run along the floor to the rear.
The normal way is to run it from front to back as the bulk of the harness is at the front and the harness for the rear is very thin so its better to run a thin harness through holes.
If you are unsure what wires go were, you can cut the harness a couple of inches from were they connect, remove the harness and fit the new one and you will have a guide of what connects to what.

[Ethel]

^^^That's a clever idea. Though it's pretty easy to work out what's what if you have a guide to the colours.

[minidaves]

normally i just skip the old loom and cut it out, then just fit the new loom in and  connect

 

dave

[robminibcy]

the rear harness is seperate from the front. And is sold seperatly as well. The rear loom connects to the main loom under the scuttle in the engine bay just above the wiper motor

[midridge2]

Post above, not if its the earlier mks, the harness is all one.

[Dan]

  In later cars (only very early cars indeed have a one piece loom I believe, even later Mk1s have front and rear looms) the body loom needs to go in from the boot and get pulled through to where the main and body looms join (which is different depending on model).  You won't get it all through the other way.  When pulling the old looms out you need to use them to drag draw cords into place in each area that you can't get to (up the pillars for example) so that you can use these to pull the new ones in.  As above I find it easier just to rip the old one out and throw the new in.  On later looms with plugs rather than individual cores at each connection there isn't anything to get wrong really, things only connect where they ware meant to.  At the main connections just join colour to colour.  Take photos of the old loom route before you start.  If you've never done one before allow yourself a day for this but it's not hard.  I have done a few, and I used to be a wireman too, so I can do one in about an hour and a half I suppose if nothing goes wrong!  Once you have gently pulled it all in (careful not to snag the cables on any sheet metal) it's just a lot of plugging.  The only fiddly bits are getting the fixed grommets into place.

 

 If the disaster you have had is only at the front you may only need to swap that harness anyway.

Edited by Dan, 19 December 2013 - 05:15 PM.

[midridge2]

In later cars (only very early cars indeed have a one piece loom I believe, even later Mk1s have front and rear looms) the body loom needs to go in from the boot and get pulled through to where the main and body looms join (which is different depending on model).  You won't get it all through the other way.  When pulling the old looms out you need to use them to drag draw cords into place in each area that you can't get to (up the pillars for example) so that you can use these to pull the new ones in.  As above I find it easier just to rip the old one out and throw the new in.  On later looms with plugs rather than individual cores at each connection there isn't anything to get wrong really, things only connect where they ware meant to.  At the main connections just join colour to colour.  Take photos of the old loom route before you start.  If you've never done one before allow yourself a day for this but it's not hard.  I have done a few, and I used to be a wireman too, so I can do one in about an hour and a half I suppose if nothing goes wrong!  Once you have gently pulled it all in (careful not to snag the cables on any sheet metal) it's just a lot of plugging.  The only fiddly bits are getting the fixed grommets into place.

Sorry Dan but not correct. one of my minis is a very late mk1 and its a one piece harness, I did a mk2 and its one piece, and I remember doing a 1275 clubman and it was one piece.
 
 If the disaster you have had is only at the front you may only need to swap that harness anyway.

[AVV IT]

If the disaster you have had is only at the front you may only need to swap that harness anyway.

That's good news, as I think it's only the front of the loom that's actually damaged. Any one happen to know where the join to the rear loom would be on an 85 Mayfair?

[Dan]

  By the wiper motor on the bulkhead, a cluster of about 8 bullets.

[AVV IT]

Thanks for all the advice guys!! 

 

Well after spending most of the day swearing, cursing and generally scraping my knuckles, I finally managed to fit a replacement front loom today (a second hand one unfortunately as times are 'ard!! ). Oddly though I now only appear to have a handful of circuits working (i.e. starter motor, window wipers, heater blower and interior light) None of the other lights, warning lights, illuminated switches etc seem to want to work, to make matters worse my multimeter's just given up too, so I'm kind of working blind now as well, does that sound like a problem somewhere obvious to any one? 

[Dan]

Just recheck the connections, start from the solenoid and work through the circuits looking for bad joints or damage. You seem to have accessory power only so the problems could just stem from the ignition switch connection and lightswitch. The main supply to the lightswitch is separate from the ignition switch supply all the way back to the solenoid.