Hardtop Fuse #25 has blown a second time

T

ted928

Member
This is my friend's 2011 E89. The first time Fuse 25 blew, the dealer replaced the fuse, a hall sensor, and closed the roof. Once again the top stopped mid-motion and my friend saw some smoke. The fuse blew. I know that wire damage near the hinge area will cause faults, but can they also blow the fuse or do you think the pump is failing?
I tested both salmon relays repeatedly and they seem fine. I will replace them.
 
Probably blown the CTM ECU…

Main relays should be replaced every 5 years or so
 
ted928 said:
I have read that a sticking relay can kill the pump. Can it also hurt the CTM?
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Sticky relays will burn out the pump and maybe the car.. I'd assume that in that a relay failed all bets would be off to the CTM come what may..and of course who knows what a 'competent' BMW dealer has done!
 
The fuse blew towards the end of the opening cycle. The roof pack had been stowed and secured, the rear module was fully open. I don't know if that is helpful information. I appreciate your help.
 
Without fault code diagnostics you’re stumbling in the dark…an e89 specfic fault code reader is a mandatory part of ownership
 
I removed roof shell #2 and all the covers in the boot and inspected all the wiring. No sign of breakage or overheating. The only issue I spotted was near the battery negative terminal where the sharp crimp was rubbing against a large red hot wire which feeds the terminal block and the front. The rubbing did damage the insulation and the was a very small black area. That could have caused some shorting. I opened the CTM and it looked fine. I installed 2 used salmon relays and successfully operated the top 10 times. I will order new relays and bolts for shell #2. I have ANCEL. If it happens again and ANCEL doesn't provide a cause, I will replace the CTM.

The code I previously got was A699 but I think that is because fuse 25 had blown.
 
ted928 said:
I removed roof shell #2 and all the covers in the boot and inspected all the wiring. No sign of breakage or overheating. The only issue I spotted was near the battery negative terminal where the sharp crimp was rubbing against a large red hot wire which feeds the terminal block and the front. The rubbing did damage the insulation and the was a very small black area. That could have caused some shorting. I opened the CTM and it looked fine. I installed 2 used salmon relays and successfully operated the top 10 times. I will order new relays and bolts for shell #2. I have ANCEL. If it happens again and ANCEL doesn't provide a cause, I will replace the CTM.

The code I previously got was A699 but I think that is because fuse 25 had blown.
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Shorting out the main power feed isn’t a great idea..
 
B21 said:
Main relays should be replaced every 5 years or so
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This period can be extended up to ~10 years, if you open it carefully and check the remaining rest of the internal contacts.

But, this is not a recommendation for Hinz&Kunz, only for techies.:rofl::rofl:
 
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The fuse has blown a few more times. It works fine for weeks, then fuse 25 blows. I replace the fuse and it works fine again. I have ISTA+ but I am not very skilled at using it. The CTM codes I get are A699 and A568. Any suggestions? Thanks
 
ted928 said:
The fuse has blown a few more times. It works fine for weeks, then fuse 25 blows. I replace the fuse and it works fine again. I have ISTA+ but I am not very skilled at using it. The CTM codes I get are A699 and A568. Any suggestions? Thanks
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You can search the error codes on here. Lots of info will comp up - or ask google Gemeni -
It’s pretty good.
 
I have done some searching on the error codes. ISTA+ says A699 means "voltage at terminal 30 under 5V", and A568 means "no message ... transmitter convertible top module". I think both of these are due to Fuse25 blowing. Why the fuse blows intermittently is the question. The Fuse25 circuit does not flex so I don't think it is shorting. Perhaps a sensor wire shorting could overload the CTM and blow the fuse. I've replaced the roof 2 wires near the bends but I still get intermittent fuse blowing. I have another friend with a E89. I was thinking about swapping the CTMs but I am not sure if used TCMs can be reprogrammed - I have seen conflicting information.
Intermittent problems suck.
 
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AI says the 3 valve solenoids are powered from the CTM so they could cause a CTM overload. AI suggests testing each coil's resistance after a few cycles to see if a coil is breaking down.
 
Just reading through this. I welcome the view from the more experience but my view is:

No sensor failure will blow a 25 amp fuse for the roof. The sensors will interface with the roof control module and these are all low voltage interfaces. Any failure to these will be handled gracefully and result in a fault code. The roof module will be designed in such a way to cope with unintended shorts on these interfaces.

A failure in the motor, relay or shorting on a high current feed is the most likely cause of any fuse blowing.
 
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Regarding the reference to fuse 25, Is this the fuse location number or the fuse rating?
Is the fuse that keeps blowing the correct amperage?
 
Matt.rowley.1990 said:
Just reading through this. I welcome the view from the more experience but my view is:

No sensor failure will blow a 25 amp fuse for the roof. The sensors will interface with the roof control module and these are all low voltage interfaces. Any failure to these will be handled gracefully and result in a fault code. The roof module will be designed in such a way to cope with unintended shorts on these interfaces.

A failure in the motor, relay or shorting on a high current feed is the most likely cause of any fuse blowing.
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Agree. I'll examine the three solenoids and the wires that power the motors.
 
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