Hi guys,

My wife's 2007 cooper keeps blowing f32 after 5 minutes of having the doors locked. If you replace the fuse and start the car, it is fine.

The car is Canadian, fairly bare bones, with heated seats. The heated seat module and the mirrors are on F32, and both work fine while the car is running.

It's my understanding that many people use F32 for a tap for IGN V+ power, which baffles me why the fuse would blow when the car enters sleep mode, since it shouldn't be powered at that point.

Perhaps there's a ground point that is back feeding that I should check somewhere? Any pointers?

 

Has the car ever gotten soaked? Sunroof open in the rain or something? There can be some sketchy connections under the carpet or places where the wires can get rubbed,...

Try disconnecting the seats and mirrors. If it goes away it is time for some real troubleshooting with a volt/ohm meter rather than frying the fusebox.

 

The car's never gotten wet.

So to my next plan of attack... I don't really want to sink another weekend into this car, but I don't wanna sink $1000 at the dealer either.

I've got a wiring diagram of the car, so I'll isolate the heater module and the mirror controls from the fuse, and once I confirm those two circuits are ok, I might just power them on their own circuit and leave the fuse out of f32.

I suspect something like a vent control that moves when the car sleeps is jammed and / or has a bad ground or something like that, and is back feedback back through that circuit. Completely a guess though, but if I work around the mirror and heated seats and everything is ok, I'll leave it like that.

 

Did it ever have an aftermarket alarm? No, wait, you said you were Canadian. Hm, you have a bare wire somewhere, but I am baffled what is pulling power when the car is locked.

 

Bump.. any more thoughts on this?

I'm going to start pulling components to see which is causing the fault. Anyone know where the seat heater module that is on F32 is located? I can't find any wiring diagrams for this either... that'd help a lot. :/

 

So, did some more investigating. When the car awakes from sleep (unlock from lock actually on the base R56) the IHS polls to see if heater modules are present. If the heater module responds, then the IHS enables the heat to that seat.

The center plug on the passenger heat module was loose. I don't know where that plug goes.

I tested the car with both seats unplugged for 30 mins, all was good. Then I plugged in the drivers side, drove the car twice for 60 mins each, all good.

Tonight, I plugged in the passenger again, tested it briefly and all is still good, so I'm hoping it was that loose plug. I'm taking the car tomorrow on some errands (PRINCESS AUTO FTW LOL) so we'll see if that solves it. If not, I'll swap the seat heater modules and retest.

Hope this helps someone in the future.

 

Car was fine overnight, fuse is good. Unless I pop back, problem solved.

TL;DR: If a low current fuse blows, check that the junction box to module plugs are tight.

 

good work on a logical diagnosis process. hopefully that gremlin won't return, and it was the plug.

up here we need them heated seats!