Many months ago, I got a check engine code for the neutral safety switch that resolved on its own, but I don't have it anymore and it seems to be functioning fine since then. Now that it looks like the 40-amp fuse powers the whole ignition circuit and therefore the primary (control) side of the starter relay too, it seems like there are a lot more places I need to check for an issue that could be triggered only when turning the ignition. I realized it must power other circuits since the power locks and windows did not work when it was unplugged, so that must be the path to ground I see from pin 5 of the starter relay when the 40-amp fuse is pulled. Your wiring diagram is very helpful as it makes clear some of the other circuits that go through that 40amp fuse. Thanks Ken, which ground would you remove? I went through all the wiring diagrams in the Haynes manual and cannot find the 40amp fuse in any other place.Īny suggestions on what could be causing this intermittent excess current draw, which even in the worst case I can get enough power to the starter solenoid by just bypassing the fuse, but that is obviously not ideal. I assume if I had a short to ground on this wire the fuse would blow immediately (and not just when I try to start the car) but I am confused why there would be continuity to ground on that wire when it seems to just run from the fuse (which is open when blown) to the starter relay pin 5 (which is also open when not turning the ignition)-so I would expect it to just show open unless there is some other path to ground not in the starter wiring diagram. I would expect both of these connections to just show open when the fuse is removed. Same thing for the pin 5 of the starter relay socket that should be connected to that fuse- it shows continuity to ground if the fuse is removed (if fuse is in it shows hot as expected). One thing that seems strange to me is if I remove the fuse that keeps blowing and test the side that goes to the starter relay, it shows as having continuity to ground. I had the starter tested at an auto parts store and they said it "failed" (whatever that means) so I replaced it, and I thought that was it but I just had the same blown fuse again, so it appears not. According to the wiring diagram (attached), this 40amp fuse seems to only serve to provide the constant hot to the secondary circuit of the starter relay (pin 5 in diagram), which when the relay is closed then goes directly to the starter solenoid. It has become more and more frequent, but even in the worst cases still where it blows 4 fuses in a row and in desperation I bypass the fuse, the car will then start. The garage estimated 7 hours work to remove and replace the dashboard and centre console hence the £800 for labour, that sounds excessive to me but it’s what they quoted.I have the car listed above that occasionally blows the AM1 40-amp main fuse when I try to start the car. Thanks, hopefully it’s the Blower Motor as they are not to expensive. Whatever is taking a 40 amp fuse out is more than likely something 'hefty' rather than low powered electronics where you would actually 'blow the fault up' rather than the fault itself passing enough current to zap the fuse. but that is getting into the realms of electronic fault diagnosis rather than automotive electronic work. Polarity reversal on electronic circuitry is bad news I'm afraid but you may get lucky and find it is something relatively simple such as a suppression diode across the motor that has failed short circuit. I don't know if the motor has any onboard electronics or whether all that is on the control unit but at least you split the problem in half doing this. I would try disconnecting the motor and then see if the fuse still blows or not when you select the fan to run.
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