'85 280SL no OVP fitted?
 

I can't find an OVP relay in my car, and my dealer says that my chassis doesn't have one listed for it anyway, so I guess I don't have one.

So does that mean my ABS has no protection from over-voltage :confused:

If so that may explain why the ABS warning light is always on, and that I probably have a cooked ABS ECU.

Any comments/confirmations gratefully received :)

85 280sl
 

have you removed the cover around the fuse box?[necessary to remove lower panel under glove box first]above the fuses,on the door hinge side you will find the ovp with red top and 10amp fuse in it.

Thanks David, and yes I've had the kick-panel out and identified every relay in there, and there's definately nothing with a fuse.
The only relays I couldn't identify were 4 identical small silver cans, that I swapped around just to see if it made any difference. It didn't :(

I've also renewed every fuse in the fuse box, in case one was related, but still no change to the ABS light.

I've even had my dealer check the ABS and they couldn't find any faults in the sensors, but didn't have old enough equipment to check the ECU or pump.

If it has it, would be behind the glovebox, there is what I would call a "shelf" behind there and would be on that.
Gilly

Incredible - you are spot on! Many thanks for that, you've put an end to two weeks of hunting.

Funny how the main dealers never know this kind of thing.

The fuse was ok, but the relay does rattle when shaken, which I'm sure is a bad sign. Although it does check out ok with a multimeter and 12v applied to it. Still, it's a cheaper thing to try replacing first than the ECU.

I owe you a beer (or ten).

For some reason what David was saying rang a bell too, but I DO remember having found one up on that shelf, I thought the fuel pump relay was up there too....
Gilly

What amazes me is that you knew where it was on a right hand drive car, surely you haven't seen many of those?

HOLY CRAP I didn't even REALIZE it was a right hand drive car.....hmmmm on second thought, no I don't think it's there, must be someplace else....:wacko:
Hey did you check out my Sprite??
Gilly

Wow yes, what a lovely car! I've only ever seen that model in it's Midget guise before, I thought Sprites had "frog-eyes"? Or is yours that mythical beast known as a Spridget?

The Frogeye or "Bugeye" as it's known in the states, was made from 58 to 61. In 61 they went to this "square body" style, right, commonly known as the Spridget as the Midget started up at that point, one of the original "badge job" cars (only significant differences in the name and minor trim differences, mechanically identical). The Frogeyes were retroactively referred to as Mk1 Sprites, as the style like mine were called Mk2, this would be the same car as a Mk1 Midget as there was no Frogeye Midgets.
I'm really proud of mine as it is a numbers-matching original, MOST of these surviving early Spridgets have had many changes throughout the years, either due to component failures or more commonly the owners just wanted the better/newer components, especially for the engine, transmission and brakes. I still have all that original stuff, including the wheels, gauges, controls, steering wheel, etc etc. Mine is an early 62, still has the 948 engine, same displacement as the Frogeye had, 50 whopping hp.
Gilly

Aaarrrrggghhhh!!!!
 

So I changed the OVP, and still no ABS :mad:

Further examination has revealed that ABS functions if I bypass the OVP, with the 12V supply from the ignition.
The big thing is, there is no 12V to pin 30, which I believe is the main supply to the relay.
I opened the socket and can see the big brown wire is connected ok, but has no power.

Any ideas where this wire gets it's power from? All the fuses have been replaced. and none of them seemed relevant anyway.

Or would it be better to install a new 12V supply to that pin?

woolf: The brown wire is a ground, power is red and comes from the battery according to my diagram, so yeah maybe tap into power whereever you can, I assume battery is in the trunk. But check the RED wire for power. If I am reading the diagram right (poor quality MB discs) it is socket #1. Socket #2 is an output to the engine computer and is also going to the ABS. That one is a 2 wire, a black wire and a red with blue stripe. #8 is a black with red stripe, comes from fuse 7. Looks like ground is socket 5? Only 4 sockets used on that connector. This all assumes it's the same as a 85 380SL (US)
Gilly

I used to have a older chrome bumper midget. It was a BLAST! It was so underpowered and handled so poorly that it was really fun. You could really have a lot of fun without going really fast. I sold it because I lived in a "upscale" apartment complex and the engine started having issues after loaning it to a friend. I knew it probably needed a pretty major tune up but my snotty neighbors gave me dirty looks for even owning such a loud obnoxious little car let alone actually working on it where they could actually see me. Wish I never sold it!

Those cars are the closest you can get to a real sports car without spending 20-30K. :)

Thanks again Gilly, mine definately has a different colour scheme it seems.
As a test I cross-wired the ignition signal wire as the power source, so that the relay still had to do it's job, and the ABS worked fine.

I won't keep it like that though, it's probably too much current for the ignition switch circuit.

My battery is only just the other side of the firewall from the OVP, so I may just run a fused wire straight to it.

Thanks again for all your help :)

Should I laugh or cry???
 

I thought I'd post the solution to my problem, in case anyone else ever has the same "fault".

I had decided to run a separate fused supply to the OVP relay, as it wasn't getting it's proper permanent supply, and I couldn't find it's fuse or source.

So I removed the battery to ease feeding the wire through the bulkhead, and trapped underneath the battery was a wire :confused: A wire with a ring terminal that looked like it should be attached to the battery post :eek: A wire that turned out to be the ABS power source :mad:

Evidently whoever changed the battery last failed to reconnect the ABS wire, and subsequently the owner had removed the warning bulb to get it through an MoT.
My local dealer had failed to spot it too, hardly surprising though. At least they had the decency to only charge me for 30 minutes work despite spending 90 minutes on it.

On the positive side, I learned quite a lot about my SL :rolleyes: