'91 940SE. Don't seem to find the 10 amp fuse that goes on the ABS relay next to the ABS controller, actually, can't find the relay or the controller! The info in the FAQ says it's on the left side by the steering column under the dash, but other sources say it's on the "right, (pass) side forward of the door on the 960s, and as the '91 SE is supposed to be more of a 960... Anyway, I don't see it on either side. Any info will be helpful.

Dear tedv,

Hope you're well. I consulted Volvo VADIS - the now-superseded dealer parts/service database - and found no diagram showing the location of the ABS control module and the ABS overload relay (used up to and including the 1993, model year, if I recall correctly). I checked various models/years, e.g., for the 1994 960 and the 1997 S90. The diagrams show the module, but not its location in the car.

The module has an aluminum case. It is about 1.5" thick (37mm), and is about 7" long (175mm). It is about 3" tall.

This module (Part #9128853) usually is above the driver's footwell, to the right of the steering column (as one faces the front of the car). The ABS module should be next to the ignition module. These modules sit in brackets, which may obscure the shape and color of the module.

The overload relay - which has an aluminum case and an external fuse-holder on top - should be nearby.

Hope this helps.

Yours faithfully,

Spook

Thank you, Spook!
Found it, all tucked up in there, a relay, hooked to the unit with a fuse protecting the relay! The fuse was blown, I replaced it but to my surprise the ABS light is still on... which is strange!

Dear tedv,

Hope you're well. You're welcome!! To get the ABS light to go out, removed the negative battery cable clamp from the negative battery terminal. Wait 15 minutes, the replace the negative battery cable clamp onto the negative battery terminal. This usually clears all codes.

Cutting electrical power to the entire car also clears the Engine Control Unit's (ECU) "knowledge' of your driving patterns, so performance may be "off", until the ECU "relearns" your approach to driving.

Hope this helps.

Yours faithfully,

Spook

Unfortunately the light is not going out--it just glows steadily and never changes. I have cleaned and checked the sensors, changed the three relays, (two by the ABS pump under the hod and the 10A on the relay by the Control Unit), disconnected the battery, and nothing...
I am pretty sure the fault is electric as the light always stays on...

How do I check the ECU under the dash?
How do I check the ABS "spider" under the hood?

Dear tedv,

Hope you're well. What trouble codes show at Code Box "A", position 3.

Do you mean to say that disconnecting the negative battery cable clamp from the battery does not cause the ABS status light to "go out", i.e., that the light comes on, so soon as the negative battery cable clamp is positioned on the negative battery terminal post?

If so - if the ABS light remains "on" after the battery is reconnected, and the car has been started - then there must be a short. If that guess is correct, there should be a code, that indicates the general location of the damaged wire.

Please post back with your findings.

Hope this helps.

Yours faithfully,

Spook

Well, the ABS light comes on as the key is turned to position II along with all the other warning lights. Upon starting the car all the other lights go off but the ABS stays solidly on. Disconnecting the battery and waiting various time periods makes no difference. The '91s have no diagnostic function to help narrow the cause of the malfunction.

Dear tedv,

Hope you're well. Thank you for the detailed report. Never having owned a '91 model, I didn't know it lacks on-board diagnostics.

Was any work done on the car, just before the ABS light ceased to go out on start-up? It is possible that during totally unrelated work, a wire was damaged, which causes the ABS malfunction.

I recall few posts reporting failures of the ABS control module (the one under the dashboard, above the driver's footwell).

The more likely source of the problem is damage to a sensor wire. Has the speedometer worked normally, at all times? I'd guess there's a speedometer sensor in the rear differential housing. That sensor also provides a signal to the ABS system. I recall posts reporting damage to that wiring harness, near the differential housing.

Hope this helps.

Yours faithfully,

Spook

The car is new to me. I, like many others, like to "save" Volvos in various states of neglect so I acquired it recently with what turned out to be many and involved issues. Being an SE doesn't help as I much prefer to tinker with the more basic 740/940 line. The SE is a 960 everything with a b230ft and a AW71 transmission. This car runs surprisingly well considering the state of neglect inflicted upon it and that is a testament to the mark: drivetrain is fine, A/C blows cold, body is nice shiny black with decent black leather only problem being a badly mended seat cushion which I am replacing. But all fluids are (were) black, brakes badly worn, rear Nivomats collapsed, fan speed only on fifth position, tires down to the belts, ignition inoperable, sunroof completely destroyed, slight front damage, bad radio, power seats issues, glove box destroyed, etc.

So, short answer is that I don't know about it's previous history: the owner was vague and apologetic after I berated him for his Volvo keeping habits and his excuse was that he was using the car as a stop gap transportation during a temporary slump in his previously stellar financial status.

Thank you, Spook, for the ECU direction!I will swap it and report back.

Check the fuse again. If its blown, it may be the relay itself. Mine kept blowing fuses as soon as you'd put a new one in and one of the internal diodes in the relay had failed.

Thank you, that makes sense! In my irrational exuberance I buttoned everything back, and now I'll have to crawl under there again...