1988 90 replacing lights with LEDs and have lots of questions

Hey all,

I've spent the day replacing the lights in my '88 90. The previous owner had done some fun things with the wiring and I'm finding it tough in places to work out what should be where. eg. I found a SPST switch behind the gauges on the dash, which was held on with zip ties. The horn was wired in some other momentary switch on the dash too, with other wires spliced which went nowhere. Janky radio install with bad speakers tying up the main harness in the central facia. Lots to fix.

Most of the bullet connectors were chopped off for one, so having to re-wire in quick disconnects.

I'm using the RoversNorth LED kit.

Is there a marked up photo of what a rear harness should look like? I have a wiring diagram, but sometimes a proper photo is nice.

So, after a day or tracing stuff I have a lot of questions:

1. The rear left light harness seems to have no ground. I've grounded to a screw the guy was using into the floor hear where the harness comes out. Is that normal? The lights do work, mostly

2. Reverse just doesn't work, although it's pretty tough to test. I put the low-range gear box into neutral, and put it into reverse, but doesn't seem to work at all. The light itself if fine if hooked up to a different circuit. I'm expecting the green/brown wire to be reverse. Is that correct? What else can I check for that light?

3. The fog light worked fine till I permanently put a quick solder splice think on it to wire it together permanently. The PO had only left a couple of inches of wire on the red/yellow line so didn't have much to work with. Now when I put the fog light on the light on the dash lights, then dies. The light at the back doesn't light. Any ideas? Previously he'd hooked up some work lights up top out the back to the fog stalk switch, so I've taken those off for the minute.

4. There was a janikly connected but pretty heft second harness connected from the back right main harness in the cabin, back down under along where the main harness runs, but it was chopped off somewhere around the middle of the cross-member. The real harness for the other side is there too just fine. What would he be running a whole other harness for? I chopped it out in my effort to de-crapify everything.

5. The main light stalk has two positions. Is that one click to running lights/side lights, and two to main dipped beams? He replaced the headlights with LEDs, but there's some weird wiring up front now too. I want to get it back to normal.

6. Probably unrelated, but the wiper motor was very very hot today, wipers weren't on. I disconnected it. I'm guessing that's a short. The wipers have worked in the past, so not sure what happened there.

7. On the wiring harness on the right some of the wires have two barrel sockets. On that side there's only one light for each so what's in the other barrel? eg. two green/purple and two red/blacks.

8. back right main harness has two grounds - what do they actually ground?

9. Under the hood he'd wired up some accessories directly to the alternator. Is that normal? Looked pretty janky. Some of those wires just floated.

10. Is it normal to have totally unused wires in the rear harnesses?

Thanks to anyone who can answer anything.

Rovers North ???
Sounds American ?
What's "Jankily" ?
Sounds American too.

On my 1994 D90, the ground is inside, at the rear on the tub in what I affectionately call the 'offside triangular wiring locker'.
I ran a wire from the earth block I installed over to the other side and fitted another one to which the near-side rear lights are connected. I also have an earth connection from the tub, behind the passenger seat to the battery box.
My towbar electics are wired into the offside triangular wiring locker.

There is a switch on the gear box that completes an earth connection for reverse.
LED's are polarity sensitive so you need to remember you are switching an earth not feeding a positive/live.

If the main harness to the rear of the car has been cut, this is an indication that the rear cross-member has been replaced at some stage. When I replaced my harness I put extra wires in for 'future expansion'.

Is the fog light a 'switch' or is it a momentary which energises a relay ?

The main light stalk takes a feed and switches it to the side lights and then through the high/low stalk on the opposite side of the column which in turn feeds the two headlamp circuits.

Calling parts of your car 'left and right' doesn't help me.
Here, in the UK, we have the drivers or offside and the passenger or nearside.
Looking at the car from the front the nearside is to the right and the drivers to the left.
If you are in America, which I suspect you are, then you have a 'left hooker' and you need to be clearer when discussing 'sides'.

Your 'barrel sockets' re likely Lucas connectors and could possibly be the fan motor (high/low speed) connectors or the windscreen washer motors (front and back).

Pictures help.

Sorry, forgot I'm on a .co.uk. Like myself the car is a Brit import to the US, so it's right hand drive. Right here meaning as you sit in it, so drivers, and left being passenger. Jankily as in poorly done - shoddily in the UK. eg. none of the screws match each other on any component. Wiring is all just electrical tape and badly twisted together wires. Random wires all over the place, etc.

'left hooker'?

Here's the rear drivers side harness. The thicker red and black are running to some work lights above the door. There's a hidden screw to ground into the body. The black/red and green/purple wires go into that black block - maybe a Lucas connector. You can also see a cut off purple and red/yellow wire.



Here's the rear passenger side. There's a screw to ground into the body.



Here's the extra mystery harness. First pic is where it's just cut off. Second it what was connected to it when it was up in the cabin. You can see in the third pic this isn't the main harness. It's something from the drivers side at the rear to half-way across the car, underneath. The correct (what I think is correct) harness is there coming out of the frame and splitting to either side.



The fuses were replaced with these two fuse boxes, but the values seem very very high. Also not really clear what they go to. A bunch were blown, which I've replaced.



I think I've sorted the fog light. Not sure how/where, but in tidying up some of the wiring around the fuses I took out some more of the PO's mess and that's stopped the fog light blowing. The fog light is a right-side switch on the column for me. The short one. The PO had wired the work lights into that switch too, so maybe fixed in unwiring those.

miktdish said:

Rovers North ???
Sounds American ?
What's "Jankily" ?
Sounds American too.

On my 1994 D90, the ground is inside, at the rear on the tub in what I affectionately call the 'offside triangular wiring locker'.
I ran a wire from the earth block I installed over to the other side and fitted another one to which the near-side rear lights are connected. I also have an earth connection from the tub, behind the passenger seat to the battery box.
My towbar electics are wired into the offside triangular wiring locker.

There is a switch on the gear box that completes an earth connection for reverse.
LED's are polarity sensitive so you need to remember you are switching an earth not feeding a positive/live.

If the main harness to the rear of the car has been cut, this is an indication that the rear cross-member has been replaced at some stage. When I replaced my harness I put extra wires in for 'future expansion'.

Is the fog light a 'switch' or is it a momentary which energises a relay ?

The main light stalk takes a feed and switches it to the side lights and then through the high/low stalk on the opposite side of the column which in turn feeds the two headlamp circuits.

Calling parts of your car 'left and right' doesn't help me.
Here, in the UK, we have the drivers or offside and the passenger or nearside.
Looking at the car from the front the nearside is to the right and the drivers to the left.
If you are in America, which I suspect you are, then you have a 'left hooker' and you need to be clearer when discussing 'sides'.

Your 'barrel sockets' re likely Lucas connectors and could possibly be the fan motor (high/low speed) connectors or the windscreen washer motors (front and back).

Pictures help.

Click to expand...

Good deduction.

Yes. thats a proper mess. Very janky.
Left hooker is a lefthand drive car.
That screw into the body on the left side is a ground.
Those 'barrels' are indeed Lucas connectors.

Could that 'extra harness' have been to power a trailer or caravan ??
It is a mess.
The original fuses may have been the glass type and the fuse boxes the PO#s attempt to upgrade to the more modern (and reliable) blade type. I agree that the fuses look far to high.


Thats quite a big job you have on your hands.
You'll need a good multimeter
This forum is a great resource to assist and we have some real knowlegeable people on here too...
Keep the questions and pics coming.

Well, all the lights are now LED and they all work except that reverse one. It didn't before either, I'd assumed because it was so rusted out, but I'll need to check the transmission position sensor and see if something else is broken on it.

Headlights were LEDs from the PO, but he messed up the headlight stalk settings. I think one click is supposed to be sides/little clear running lights, and two clicks is main beams dipped. Then fulls are the indicator stalk forward. Well both headlight stalk clicks do the same and turn on the dipped and side lights. No difference between them. Not a huge deal, but annoying.

Polarity on the LEDs got me a couple of times, and interestingly up front on the side/running lights one was one way and one was the other.

Passenger rear is now a bit neater. Doesn't look it, but actual plugs on everything now, so lights can be removed in the future without cutting, and those plugs are now solder sealed to splice the wires and then heat-shrunk-tubed. I need to find some grommets for the holes and a nice way to tidy up the loose wiring, or hide it.



Up front, hidden behind the lights in the wings is still bit of a mess.

Driver's front -


Passenger sides has some extra random wiring too. Some extra red wires that are barely hanging onto the wires that become the indicators, etc. Within the wheel well and behind the front lights you can see it's a mess, with some very shoddy splices. I had thought/hoped behind here was better, but it's pretty crap. I'll have to tackle these next. The actual connectors and fittings are where I've replaced the lights from the front and put proper splices on. There seems to be a lot more wiring necessary for just 3 lights in the wing, and a side indicator/repeater.



The harness on the passenger side has some fun things too. It's not easy to see, but this is where the front passenger light mess starts. One of the thicker tubes feels empty and goes nowhere. One of the reds comes off the alternator and goes nowhere. The thicker red comes off the alternator and goes up front somewhere, I assume feeding a headlight. There's some spare connectors floating around. The horn is cut off because I cut it off. The horn was a custom momentary switch drilled into the top of the gauge cluster, and then when I pulled off the dash it turns out there was this switch hidden behind the gauges that the horn was wired through. It also had another loose wire going nowhere from the switch. Horn isn't that important, so I'm buying a better switch and will wire it up properly.



Then some random wires just loose. First is a purple one coming from the passenger wing, second just hangs loose underneath.



Looks like next up will be:
1. Fixing the wiring in the front wings to un-jank it.
2. Putting the horn back
3. Replacing the side repeater indicators with LEDs
4. Installing an accessory fuse panel in the battery bay
5. Rewiring in the rear work lights, and flashing orange fun lights with proper switches.
6. Finding a way to tidy up the wiring at the rear.
7. The rear ground screws are both the wrong size. One too loose, one too tight. I think I'll replace with bolts and star washers
8. Installing front Hello driving lights on the bumper winch bar
9. Replace the winch which is broken
10. Replace/fix the wiper motor, which burnt out and is leaking oil/grease
11. Install rear brake light above the rear door, I want one up high
12. Install reverse camera