What can cause a ECM relay to stick?

Old 11-12-03, 03:13 AM
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What can cause a ECM relay to stick?

I am working on a 97 Isuzu Rodeo. The problem started out as a no start. Then we took the dash apart, checked all the wiring and didn't find anything worng. Hit the key and it started right up.

We have gotten to the point that the ECM relay is sticking even with the key off and out of the ignition.

My first thought, bad ignition switch, we unplugged the ignition with the relay stuck in the closed position, it stayed closed. We unplugged the relay it opened. We also checked the ignition switch according to the manual. It's ok.

The wiring to the relay is good. I checked another rodeo and the four terminals that the relay plugs into has the same voltage on them key on and off.

What could be holding this relay in??? I'm at my wit's end.
Old 11-12-03, 12:08 PM
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...are easily diagnosed...half of it is controlled and the other half is doing the work...controlling a large current circuit with a low current one. have you tried substituting another relay? Look in the relay center and find one with the same part number and swap them. a relay that sticks is bad...a relay that is turned on when it shouldn't be indicates a wiring problem. according to the wiring diagram power feeds the control side of the relay when the ignition switch is turned on...so if the relay is "on" when the ignition switch is removed from the circuit, you disconnect the relay and check for voltage on the blk/yel wire...if no voltage, the relay is sticking and is bad. if you still have voltage then there is a short to voltage on that black and yellow wire. hope this helps...
Old 11-12-03, 12:40 PM
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Yes we tried a different relay, it did the same thing. So I told him to start pulling fuses until it unlatched. It never did.

He found the problem this afternoon. Bad ground between the battery and the engine block. I asked him first off when he said he was having electrical problems if he checked his ground connections.

Oh well it's running.

Thanks for the reply.
Old 11-12-03, 08:11 PM
mike from nj
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you might want to call a dealer with your vin #.

i can remember doing negative battery cable recalls, just not the specific applications that were covered.

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