4 months ago I bought an old 1992 GLS. It has been running like a dream. Today when I switched off the ignition I could still hear a whirring noise and on opening the bonnet found that a particular component seemed to be humming away merrily. It has never happened before. What is this part (see attached) and what do I do about it? Please excuse my lack of mechanical knowledge...

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I believe that is you ABS modual... but dont completly quote me on that.

Pretty sure

Oh... ok... So any idea why is it whirring away and is it gonna run down my battery overnight?

If it is your ABS.. it shouldnt, it really shouldnt run at all after you shut off your car unless there is something worng with it... but you really shouldnt hear anything from that unit... next time it happens make sure thats it.

It's been running for about an hour so far and still going... no key in the ignition. Still whirring away...

Ok, if you feel up to it go to the top of the modual and disconnect the wiring from the connectors on top. Since you have your ignition off you shouldnt hurt anything but disconnect the connectors and see if it shuts off, you may have a bad relay somewhere. But if you feel at all uncomfortable doing your own diag, take it into a shop, you dont want to mess something up and than send it into someone to clean up the aftermath. Some shops will charge you more if they know you did some of the damage doing something you dont know anything about.

Good Luck

The ABS unit just kept whirring and getting very hot so I disconnected the battery and left it to cool down. When I reconnected it a few moments ago the unit didn't buzz again. A gentle test drive shows the brakes are still working and when I switched off the ignition everything seemed to be back to normal. I will take it to a garage tomorrow and get it looked at properly. Thanks for your advice earlier... I appreciate it.

Yu will most likely need to replace the ABS controller module. Wut is happaning is that the abs electronic controller is keeping the ABS module active even after the vehicle is turned off. The ABS controller is powered at all times. On most models the abs controler is under the rear part of the center console.

Sawatdee and Khorb khun khrab KiT TeUnG 2549... :) I will get it looked at by a mechanic as soon as I can... How is life in Chiang Mai by the way?

Sawasdee Krub , Mai Bpen Rai Krub. Chiang Mai is great, Thanks for asking Poot Thai dai mai?

Pomme poot pa sah Thai nitnoi khrub... fairn pomme bpen khun Thai... :)

Ahhh , kaung koon fairn kon Thai. Awsum. Hope yur issue gets sorted.

Choke Dee,

Kongkit

most likely a fused motor relay is causing the issue.

Well by all means do explain .......


As of i no the relay gets its signal input frum the controler , teh relay, just send a power input but no actual function. The ABS controller itself would activate the abs pump motors to make the whiring noise.

do you actually know anything about these cars? I have yet to see you post something that makes sense.

here it is for you...
the ABS controller activates a relay. there are 2 primary relays, one for the motor, and one for the valves.
the motor requires a high amperage. what happens (commonly AGAIN) is that the contacts fuse from the continuous high current arcing that takes place when the relay is activated.
thus, the motor continues to run as the contacts are now fused into one continuous circuit.
the end.

Since Ive worked on mitsus forever, i HAVE seen everything that can break actually break. And i used to replace a LOT of motor relays on these very old and very primitive ABS systems.

NO need to get hostile, i have posted many relevant answers and insight on these cars , almost every model. Yu just leave very open ended very simple answers with the least bit of explination or example.

The ABS controller is powered even on key off . The electronic servos in the abs pump are controlled thru by the controller. The relay for main power to the unit is also turned on by the controller/abs control module. This would be the reason it can operate the bypass pressure servo even with the engine/key off.

The onlee reason the bypass servo motor can stay stuck , even via the relay was if the abs controller was kept the bypass servo active after key off also with the relay active.

So before yu fly off the handle parts changer , we are here to help people , not question if they have had any good input to help other or not. cause i think i have in many areas a well as other here.