No fogs or reverse light and abs light on all the time.

[MiniC]

I've got a weird one my cars in for Mot, the rear fogs got work neither do the reverse lights also when the car is on the parking brake light abs light and (!) light stay on the dash. The front fogs won't turn off with the switch help please.

[BenHar]

The fog light problems can probably be fixed by cleaning the switch.

Ben

[MiniC]

took the switch apart had a fair bit of corrosion put it back together and nothing. the front fogs stay on with the lights and i have no dipped beam, could it be a dodgy relay? ive also cleaned the headlight switch to no avail.

[Speedtouch]

Possibly, or a bad earth - check all brown wires in the vicinity of the lights.

[Brianmoooore]

The electrics on E30s are extremely well designed and generally extremely reliable. The few faults that do occur, and the reasons they occur, are usually well documented, but you seem to have an unusual collection here!
Did all these faults occur at the same time? With multiple faults you usually look for a common cause, but I'm struggling to see much in the way of connections between these.
Are you sure the correct relays are in the correct places in the fusebox? Both K4 and K8 should be black 5 pin double pole relays, NOT change over relays
Rear fogs: I take it the instrument cluster tell tale doesn't light up and that fuse 15 is intact? Pull out relay K4 and use a wire link to connect pins 30 and 87b of its socket. Push in the rear fog switch. Do the rear fogs or/and tell tale light up? Connect the wire between 30 and 87. Do the dipped headlamp beams light up?
Front fogs: You say they won't turn off with the switch. Do they go off when the ignition is turned off? Do they go off with the ignition on and the plug pulled off of the foglight switch? Do they go off when you pull out relay K8?
Three warning lights that you say remain illuminated are the three that are legally required to have a 'test' function to ensure that the lamps are working, every time you start the car. They come on with the ignition, and go out when sufficient voltage, produced by the alternator, appears on the small blue wire from the alternator that controls the battery warning lamp.
Anything odd about the battery warning lamp or the charging of the battery? The usual cause of this happening is a duff alternator regulator or failure of one of the associated diodes, but it could also conceivably be a fault with the electronics on the SI board

[MiniC]

Brianmoore you are a saviour. Sorted the fogs and dipped turns out k8 relay was faulty. Embarrassingly I hadn't put in number 15 fuse and a few connectors were corroded. Although I don't know if the reverse lights come one. Does the car need to be running? And I have a constant abs light on the dash MOT failure.

[Brianmoooore]

Forgot the reverse lights. Check fuse 10 for a start, and if its OK, pull up the bottom of the gear lever gator, and locate a two pin plug and socket near the front of the gear lever with two coloured wires going to one side of it, and two plain black wires going to the other, that come up from underneath the car through the rubber gear lever grommet. Pull the plug and socket apart, and use a piece of wire to link together the two pins of the half with the coloured wires. Do the reverse lights work with the ignition on?
ABS lamp: Does this come on with the ignition and stay on until the ignition is switched off, or come on with the ignition, go out when the engine is started, and come on again when the car moves?

[MiniC]

I'll check the reverse lights tomorrow but the abs light is on and stays on all the time.

[Brianmoooore]

There are two slightly different ABS systems used in E30s, with a changeover of about '88. IIRC, your car is '87, so I'll assume it's the earlier set up.
Remove the access panel above/behind the glovebox, and look for a silver 'relay' clipped to the top side of the body coloured piece of metal that the glovebox catch is bolted to. This relay contains a non replaceable fuse and a zener type diode, designed to protect the ABS ECU against voltage spikes - the type produced by jump starting a car or using your car to jump start another car.
There should be 12 volts+ (straight from the battery) on the red wire (pin 30) and also 12 volts + on the red/yellow wire (pin 30A) when the ignition is on.

[MiniC]

Alright checked it all yeh if I link the reverse wires they come on. And I'm getting 12v on the red wire but only like 0.9 on the red/yellow one. Dead relay?

[MiniC]

Alright did a little research and took the abs relay apart and the integral fuse wire has been popped. Where is the best place to buy a new one. Euros?

[Brianmoooore]

I doubt if they are available anywhere except BMW and second hand.
It's possible to fit an external fuse (8 amp) to repair your existing one, as long as the zener diode hasn't gone short circuit (unlikely).

[MiniC]

Alright how would I fit an external fuse?

[Brianmoooore]

You can short out the internal fuse completely with a bit of wire, and then fit a 8A fuse in series with the red wire. It's essential that the relay is not used without a fuse, because it will cause a loom fire if the diode ever goes short circuit, or the alternator regulator fails.
Alternatively, you can convert to the later system: Discard the relay completely, cut the red/yellow away from its socket, and extend this wire to the pin of the DME relay that has a red/blue wire connected to it.
There is a wiring duct at the back of the glovebox area that goes up into the fusebox that can be used to get into the engine compartment.
On the factory later loom, the wire connects to pin 20 of the C101 engine loom socket, and the engine loom has a similar wire from the DME relay to pin 20 of the C101 plug.
You also need to cut the brown and brown/yellow wires away from the ABS relay's socket and join them together.

[Brianmoooore]

From the 'parts wanted' thread, I see you say you've done the above, and the light is still on.
I have the early and late circuits diagrams in front of me, and they are identical, apart from the system getting its control power supply from the DME relay in the later version, instead of the dedicated ABS relay in the early version.
I did say "cut the red/yellow away..." in my last post, where it should have said "cut the red/yellowS away......" - there are two of them, and they both need to be connected to the new wire to the DME relay. I take it you have connected both of them?
There is, of course, still the fact that we don't know what blew the fuse in the ABS relay in the first place. In most cases it will be as a result of a voltage spike, caused by someone doing something to the car that they shouldn't, such as jump starting it, or using the car to jump start another car, but we can't assume this, so it's possible that there is actually a 'real' fault with the system, although I've never come across one, other than sensor related, and the E30 system doesn't flag these until the car moves.
The fault light can either be turned on by the ABS ECU (pin 29) or the ABS pump assembly under the bonnet. There is a diode in this (inside one of the two relays under the cover) IIRC, that can allegedly turn the light on if it fails.
The wire from pin 29 of the ECU and pin 7 of the pump plug is green/red, and should be at zero volts when the ignition is turned on (light on), rising to 12 volts when the engine is started, turning the light off.
The ABS ECU knows when the engine is running by the blue wire connecting to pin 15. This wire comes from the D+ output of the alternator, which is the same output that controls the battery warning light*, and should be zero volts with the ignition off, zero volts with the ignition on, and 12 volts+ with the engine running.
*Your original post in this thread was about dash warning light staying on. These are also switched off by the alternator D+ output. How was this resolved?
There should be 12 volts + at pins 6 and 12 of the ABS pump plug at all times, and 12 volts + at pin 10 of the ABS pump, and at pin 1 of the ABS ECU with the ignition switched on.
Pin 8 of the pump and pins 10, 20 and 34 of the ECU should be zero ohms to earth (body).

[MiniC]

Alright I've read all of that and will check it all tomorrow. I looked at the relay plug and from memory it only had one red/yellow and the other was solid red at a constant 12v.

Also when I got the car there was a second what looked like damaged ecu don't know if it was abs or main. I hope that isn't dodgy. And yeh the light is on constantly on the dash.

[ChrisHC]

Arising from the above, is there a safe way to jump start an E30 or use it to jump start?