The power circuit to the pump is quite simple and power is fed from Fusible Link 7 on the battery terminal block through a relay. This 100A fuse is (AFAIK) dedicated to the AYC pump. Also the pump ground is #10 which only serves the pump (and washer pump). So sounds like the pump is taking excessive current, not enough to blow fuse but enough to pull down battery voltage. I'm guessing you have boot battery with long cable which probably makes the effect of excess current worse on voltage to rest of system.
Could be a simple fault like a bad battery or corroded connector on battery - bet you've already looked at that though
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After that for me it likely a pump fault. Doubly so because it's on in many cases when it shouldn't be which suggests it's not generating pressure. Could also be sensor issue but then that wouldn't cause excess currents.
If there is no pressure then I'd expect some AYC fault codes. Have you tried flashing out any codes?
I'd be tempted to disconnect the pump and feed it directly from the battery and see what heppens when its running, ie does the voltage drop. If it runs and voltage is steady then a possible cable loom issue somewhere?
Hope that helps
Cheers
Rich
Could be a simple fault like a bad battery or corroded connector on battery - bet you've already looked at that though
.After that for me it likely a pump fault. Doubly so because it's on in many cases when it shouldn't be which suggests it's not generating pressure. Could also be sensor issue but then that wouldn't cause excess currents.
If there is no pressure then I'd expect some AYC fault codes. Have you tried flashing out any codes?
I'd be tempted to disconnect the pump and feed it directly from the battery and see what heppens when its running, ie does the voltage drop. If it runs and voltage is steady then a possible cable loom issue somewhere?
Hope that helps
Cheers
Rich
