1989 Crossflow Main Wiring Loom

[Greywolf]

I am about to carry out replacing my main wiring loom (New one supplied by Redline).

Following advice received I intend to remove the dashboard, turn it 180, for easy access to all the gauges. Are there any other hints/tips/advice that will make this task easer? Any pitfalls that I should be aware of?

 

Steve

[Crudders]

An alternative to removing the dash is to make the scuttle top removable, by drilling out the rivets fixing it to the bulkhead and replacing with M4 or M5 rivnuts and machine screws. If you have the knee panels in place these will also need to be removed to get to the pair of nuts on each side holding the scuttle down to the chassis tubes. On an '89 car you probably have the downturned tabs on the scuttle sides with a large flange rivet, which on my car have been replaced by stainless button head machine screws into tappings in the chassis tubes. This will make future maintainence much simpler without having to drill out any rivets (or working upside down with your head in the footwell, which isn't much fun).

 

Cruds

[Molecular--Bob]

I have just done this on a 1990 chassis. Do NOT remove the old loom until you have the new loom. The spec is the same, but the layout is slightly different, and the fuse box is modern and set out differently. I found it easiest to replace one switch or dial at a time, unplugging the old and fitting the new. I cut the old loom once i was happy that the new one fitted well. One or two fittings are wrong as well. you will have to add connectors for the brake switch, and remove a plug for the washer bottle as ours have spade connectors. I have had to check my old loom a few times as the colour codes on the new loom are the same, but age had fadded some of the originals.

 

I recommend the removable scuttle, you will not have enough wire length to easily do what you suggest.

[Molecular--Bob]

I ended up getting a new vertical panel as mine had so many holes and additions over the years, get it direct from arch as Caterham don't list it, about £30.00 with vat and delivery I think.

[ECR]

I found it very useful to have a bunch of 4" (?) cable ties to hand to temporarily hold wires in place.

(They were apparently invented for installing aircraft looms ....)

[Phil B]

Take lots of close up pictures before you disconnect anything. Especially useful if you get one of those phone calls just after unplugging something and a clip has just sprung across the garage. Yep been there too!

 

You shouldn't need to drill out rivets to separate the scuttle top from the firewall, you can remove the complete scuttle and firewall complete.

 

If you are replacing the complete loom, you will need to gain access to the transmission tunnel to feed out the old rear loom and feed in the new one. There may well be a multi-plug just inside the transmission tunnel that splits the rear (there was in mine (1985). The engine bay part of the loom however was wired directly to the dash section, so the was an awful lot of wiring to feed through from inside the car into the engine bay.

 

Does your car still have the "Otter" resettable circuit breakers mounted on the engine bay side of the firewall, or do you have more modern replaceable fuses? My car had the "Otter" CBs and they are made of unobtanium, so I replaced them with an 8 way blade fuse box mounted in the same place.

 

If you do decide to replace the dash panel itself be aware that there are many variations depending on type of instruments, number of switches and whether your warning lights are in the main gauges or mounted separately between them.

 

regards, Phil

[ECR]

From what I remember (1990 crossflow) the main loom passes throgh the firewall so the complete scuttle/firewall cant be removed intact. I agree completely about taking photos,it was invaluable for me

[andy couchman]

Can I ask what the cost is a) of the new loom and b) what other bits I'd need please?

 

If anyone has a photo record of doing this that would also be much appreciated. Have been thinking about doing it to my 1988 car (but also removing any unnecessary wires and coming up with the best solution to add in the newer 3D engine management system).

 

To be honest, I've been a bit scared of how much work this might entail...

 

I also replaced the scuttle rivets with bolts (small stainless cap head bolts which look great) and would recommend that.

 

Andy

[Molecular--Bob]

Hi Andy

 

I got my "crossflow with VDO instruments" loom for Around £240.00 delivered from Redline.

 

I have a DTA ecu which runs off its own sub-loom which has its own power supply from the switched side of the FIA switch. I use two relays, one for switched power to the ecu and coil, and one to run the fuel pump, which is ecu triggered. All of these are in the engine bay. I used the old coil connection +ve to switch the relay, and the negative (black and white trace) for the ecu tacho out signal. i used a seperate fuse box but if i did it again i would use the relay blocks that have fuse holders built in as it reduces clutter and allows shorter wire runs.

 

My installation was complicated by the need to un-pick the new loom to make changes required for the way my zetec is installed, but it should be plug and play for a crossflow replacement. I also had to crimp on a few spade terminals and change the lighting bullet connectors for the econoseals used in later light fittings as i had done this on my old loom a few years ago and didn't want to buy new lights.

 

You will also need to add a fuel pump wire to the rear if yours is electric. I just cable tied mine to the new loom and covered it with a length of split convoluted tubing before i ran it down the tunnel.

 

Biggest issues are opening up the tunnel to get it secured, and removing the carbs for running the loom down the chassis rail. I drilled the rivets out of the tunnel cover on the drivers side and bent it upwards a little to give access, and will be riveting it back together this weekend.

 

I would be tempted to get the 3d ignition side working on your car, then it is just a module to re-attach to your new loom once it is in place.

[andy couchman]

Thanks Bob.

 

This may well be my next winter project...

 

Andy

[Greywolf]

Update on progress - My new loom turned up promptly from Redline (£240+£12 postage) and I have taken the advice offered:-

1. Rivets drilled out, including the 2 big ones at the sides and the 4 nuts, scuttle now removed. M4 Rivnuts and machine screws ordered along with a Rivnut insertion tool (£9).

2. Have taken plenty of phots of all the important places for future ref.

3. Old loom now out but still connected where possible, will fit new loom and once lined up will then remove one at a time of the old connections and replace with new.

 

Question: I have snipped the smaller branch loom going to the rear just in side the gear stick housing, ensuring I have plenty of length to work with. All these wires look in good condition. Should I snip the new loom and join to the good condition rear old loom with a suitable connector? Or carry on all the way with the new loom to the rear?

 

Guys thanks for your help and advice, most graciously received - thank you all.

 

Steve

[Molecular--Bob]

If you have bought new then use it i think, joints just introduce points of failure. It also seems to be the rear of the loom that suffers bad earths and chafing more than the front of the car.