Hello, looking for help diagnosing a 2001 ML320. The secondary water pump continues to run after shutting the car off. I know it should run for a few minutes, but now it will not shut off at all unless you unplug it. Replaced relay (K19) and same result. No error codes. Tips on where to go next? Thanks!
aux water pump running
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If the temp is below 100C the pump runs for 5 min, if above the pump runs for 10 min. Check the time properly.
If the pump doesn't stop replace K19 relay with a similar one from the fusebox (for diagnostic purposes) & see if the pump stops after 5 min.
And welcome to the forum
If the pump doesn't stop replace K19 relay with a similar one from the fusebox (for diagnostic purposes) & see if the pump stops after 5 min.
And welcome to the forum
Fashion a 6" piece of 16gauge wire with spade terminals attached. With the key out of the ignition, remove relay #19 .
Insert one end of the jumper wire into slot 85 and test the other end for 12v. Remove wire and insert in slot 86 and test for GROUND.
The GROUND signal to the relay is provided by the AAM to initially turn it on and then after eng. shut-off it will continue providing a ground signal for a specified time and then remove the ground signal to shut the pump off.
Post back with results.
Insert one end of the jumper wire into slot 85 and test the other end for 12v. Remove wire and insert in slot 86 and test for GROUND.
The GROUND signal to the relay is provided by the AAM to initially turn it on and then after eng. shut-off it will continue providing a ground signal for a specified time and then remove the ground signal to shut the pump off.
Post back with results.
Attachments
If you are absolutely sure that the pump does not shut down after approx. 3-4 mins. then the only explanation for this is that the AAM is internally faulty.
Try and reset it in the following manner with the key out of the ign.:
1. connector, fuse and relays in place.
2. remove K19 relay and insert test wire into slot #86 . and verify that there is still a GROUND signal. If so............
3. remove the fuse box GROUND cable, then reattach (no need to put the nut on) and test the wire again.
4. do this a number of times to see if the GROUND signal is removed.
If the ground sig. is not removed, you have a faulty AAM.
If it does remove the ground sig. then it could be a one time problem or it could recur at a later time. You will have to keep an eye on it.
Try and reset it in the following manner with the key out of the ign.:
1. connector, fuse and relays in place.
2. remove K19 relay and insert test wire into slot #86 . and verify that there is still a GROUND signal. If so............
3. remove the fuse box GROUND cable, then reattach (no need to put the nut on) and test the wire again.
4. do this a number of times to see if the GROUND signal is removed.
If the ground sig. is not removed, you have a faulty AAM.
If it does remove the ground sig. then it could be a one time problem or it could recur at a later time. You will have to keep an eye on it.
Attachments
I don't see that our '99 ML320 has a secondary water pump but it sounds like a good idea. The closest thing I can remember is that some of my Corvettes kept the electric fans running after shutdown when out in the Imperial Valley in the summer. When that happened I started the engine to run the water pump, just in case.
What I have always wished for is a pre-start motor oil pump. May not be necessary, though.
I assume that if it would reduce engine wear the high-end cars would have one.
What I have always wished for is a pre-start motor oil pump. May not be necessary, though.
I assume that if it would reduce engine wear the high-end cars would have one.
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