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Which ground? Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Wed, 27 Aug 2008 17:58:34
In Reply to: ABS pump motor, Dale Montondo, Wed, 27 Aug 2008 08:33:57 Members do not see ads below this line. - Help Keep This Site Online - Signup |
The ABS pump pulls a lot of current, but it couldn't be excessive or the fuse would blow. It sounds like you have a different electrical problem. It's not the battery connections, because a bad connection there would result in the car not cranking - that's a LOT more current than the ABS pump pulls, even a bad one.
The first thing I'd check is the ground strap for the alternator. Then check the connection from the engine to chassis. Next, check the grounding for the ABS pump and the ECU. The ABS pump and ECU don't share grounds, but something flaky could be going on.
After that, I'd suspect the ignition switch. The switch supplies current for both the ABS system and the ECU (among others).
If you can replicate this reliably, I'd take a simple 12 volt trouble light and start isolating. Put it across the battery and see if it flickers when the pump kicks in. If it does, the battery is shot. Start moving the light to see where it does flicker. Find the back of fuses, because most have a little slot where you can measure the voltage. If the light doesn't flicker when the pump kicks in on a non-switched power bus, like the Hazard Lights, but it does flicker on a switched power bus like the ECU fuse, then it's likely a weak connection in the ignition switch. There is a set of contacts that closes when the key is in the ON position to supply switched power.
Now, the ABS pump isn't on that switched line, but it is controlled by that line. The ABS pump is a direct tie to the battery. But it wouldn't hurt to check the +30 bus (always powered).
posted by 76.196.10...
, Wed, 27 Aug 2008 17:58:34 <-- Viewing This Message
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