Hello Brickboarders,

I've been driving around with my ABS light on for a couple of years now and I've decided it's time to fix it.

(I *do* have ABS, unlike Garrett http://www.brickboard.com/RWD/volvo/1561381/220/240/260/280/abs_light.html I mention this thread because of a digression into '91 model trivia which might be relevant.)

The ABS light came on in some peculiar circumstances. A few years ago my speedometer was working intermittently and my mechanic at the time said he suspected that the speedo cluster (K9800) was bad. I found an instrument panel from an 89 with the same speedo cluster number (K9800). I even emailed Art to see if the cluster would work. He said it would to the best of his knowledge.

I passed the whole instrument panel to my mechanic expecting him to take the speedo cluster out and use it. What I believe he did instead was put the whole instrument panel from the 89 in. This didn't fix the speedometer problem, so he put the old instrument panel back in. The intermittent speedometer ended up being a bad wire.

When I got the car back the speedometer was fixed and the ABS light was (and still is) on.

I've read through the lengthy ABS fault diagnosis procedure in the Bentley, but I thought I would ask the brickboard before embarking on that epic.

Is there a specific fault in the ABS system that I should look for given my story?

Also an interesting question, but requiring some speculation:

What exactly did the mechanic do with the instrument panel out of the 89?

Thanks,
Spencer

PS I have decided that I am my own mechanic now, even if all I've really ever done in my 240s is stuff like brakes, spark plugs and exhaust work. Oh yeah... I cleared some SRS codes today, but that's another story involving the same mechanic...

First thing I thought of was to take a look to see what sort of damage could occur if the 89's cluster was installed in your 91. Well, it looks like none just where the ABS light is concerned.

In the '89 the light where your ABS light is, is the CEL. Both lamps activate the same way; by supplying ground externally through pin 32/3 on the semi-circular connector. So, it doesn't seem like having the wrong label on the light would kill the diagnostic circuit that finds its way to the instrument cluster on that pin 3 -- through a green wire.

Best advice I can think of giving you is to try to trace that wire, looking for evidence your tech was trying to make things work with the '89 panel. Pull that wire out of the housing (release the tang) and your ABS light should go out.

Now, the question I have in mind is, does the ABS function? Have you given it a test? I would presume so if you've gone to the trouble of sorting through the ABS diags.* Can't really help you with experience there, but if the ABS doesn't work, I would expect that green wire to supply a ground to the instrument cluster, lighting the ABS light.

cluster map

cluster physical

ABS map

ABS physical

*Edit: Just re-read your OP. I see the diags are yet to be done. Isn't there a fuse that protects the ABS unit from overvoltage which is a common culprit? That might be a quick leap to conclusion. Sorry, no personal experience on this.
--
Art Benstein near Baltimore

16.5 Expert: An "ex" is a has-been and a "spurt" is a little drip under pressure.

Alright, I replaced the fuse and the ABS light went out. So it seems like the replacement of the cluster was a red herring. Perhaps the blown fuse was just coincidental.

Thanks for your help. It's a little weird driving around with no dash lights on.

The 10A fuse which piggybacks on the surge protector ( which itself is attached to the ABS computer) was blown. I'm off to buy two.

Edit: Relying on the local gas station in Santa Monica to have a fuse was a mistake. It'll have to wait until tomorrow.

Art,

Thanks for your reply and the diagrams. My post has come at a somewhat awkward time for me, since I was driving across the country to LA. I haven't had a chance to look into things again.

As a start I will take a look at the green wire and check the fuse and report back soon.

-Spencer

Art, not to get too off topic, but where do those diagrams come from, greenbooks? Where ever they're from, I need to get 'em. Those look super helpful!