w126 OVER VOLTAGE REGULATOR AND/OR RELAY

Apr 01, 2005 3 Replies
300 sd, 1985. where is the over voltage regulator? today, my car suddenly failed to start (as if it had a dead battery), once jumped, it ran fine, but the radio turned on and off by itself a few times and then the antilock light came on... later it would not start again, and when jumped, the antilock light came on again... ran it for an hour and again, did not start... my guess is the regulator or relay... not sure where to find the regulator pls help

there is a regulator/brush pack on the back of your alternator that can be easiy replaced. It costs 20 or 30 bucks.

Run, don't walk, to the nearest Catholic church and find a good exorcist (as soon as they finish their last respects for the current Pope) If you have the original radio, the on/off switch is an honest to gawd mechanical switch, and in my expert opinion, your SD has become posessed.

Of course there is another possibility. Have you noticed any bright lights in the sky lately? Any short grey-skinned guys with really big eyes hanging around? That could explain a lot. Thank goodness you have on SD, which, once running, is ideal for alien encounters, since the engine needs no electricity once running.

Actually, a cheap voltmeter might answer a few questions for you before you start replacing the wrong parts. Even better, many auto parts stores will hook up a tester for you and give you a few more clues. Be a bummer to replace a bunch of non-refundable alternator-related parts only to find you have a battery with an internal short.

Conrad

The over voltage protection relay, as its name says, is to protect other expensive components, like the ABS brain or the engine control module (ECM) in the gas cars. It does not control the starting circuit.

Check the battery. Low voltage will turn on ABS light.

If you still want to check the OVP relay, it should be in the component compartment (between engine and passenger). Probably in the center, with one or two fuses on top.

jzwiller wrote:

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