2000 Boxster C3 Fuse Blowing

[baldymech]

2000 Boxster---Windows not working and no interior lights. C3 fuse blown. Replaced fuse but it keeps blowing. Checked module under drivers seat and there is no evidence of water. Ordered new ignition switch on a wild chance this could be the problem. Does any one have any ideas what else I might check.

Thanks

[Loren]

:welcome:

C3 -- 15 A CU CL/Alarm Power, Window, Inside Light

You will likely need Durametric, a Porsche PST2, or PIWIS to further diagnose.

[baldymech]

I had friend who is a tech at a porsche dealer look at the problem . What he did is replace the C3- 15 amp fuse with a 30 amp fuse and the windows, door lights and alarm all started working. He then replaced the 30 amp with a 15 amp fuse and it has been working just fine for the past week. He said if it was a direct short to ground it would have blown the 30 amp fuse. Does anyone have any comments or reason for this fix.

[Loren]

I had friend who is a tech at a porsche dealer look at the problem . What he did is replace the C3- 15 amp fuse with a 30 amp fuse and the windows, door lights and alarm all started working. He then replaced the 30 amp with a 15 amp fuse and it has been working just fine for the past week. He said if it was a direct short to ground it would have blown the 30 amp fuse. Does anyone have any comments or reason for this fix.

Sorry, that does not make sense - unless he fried whatever was causing the problem and just does not know it yet.

[joecal]

I had friend who is a tech at a porsche dealer look at the problem . What he did is replace the C3- 15 amp fuse with a 30 amp fuse and the windows, door lights and alarm all started working. He then replaced the 30 amp with a 15 amp fuse and it has been working just fine for the past week. He said if it was a direct short to ground it would have blown the 30 amp fuse. Does anyone have any comments or reason for this fix.

I had the same problem and I even had the CLU repaired and it was still blowing the fuse. It was driving me nuts, I reluctantly tried your mechanics advice and it worked. Thank you very much, I was going to take it in tomorrow to a local shop. The windows are only going up half way now so I'll have to figure that one out.

[mikefocke]

Maybe corrosion between the contacts and the fuse cause resistance/heat and fry the fuse. Then removal/swaps cause more solid contact.

[Loren]

Guys - please check the date on the post before you reply. The original poster has not been back in 2 years...

[joecal]

Maybe corrosion between the contacts and the fuse cause resistance/heat and fry the fuse. Then removal/swaps cause more solid contact.

Could be Mike, it's not blowing the fuse anymore, I did spray some contact cleaner on the fuse contacts. I hope I didn't do any damage though, my windows are both stuck in the down position. I know you're very knowledgeable about these cars. I read your write up about installing a new top which I'm in the process of doing. I replied to this post because I was having the same issue as the original poster, just 3 years later.

Edited August 14, 2015 by joecal

[JFP in PA]

 

Maybe corrosion between the contacts and the fuse cause resistance/heat and fry the fuse. Then removal/swaps cause more solid contact.

Could be Mike, it's not blowing the fuse anymore, I did spray some contact cleaner on the fuse contacts. I hope I didn't do any damage though, my windows are both stuck in the down position. I know you're very knowledgeable about these cars. I read your write up about installing a new top which I'm in the process of doing. I replied to this post because I was having the same issue as the original poster, just 3 years later.

 

 

If memory serves, there are only a couple of things on the fuse circuit, like the windows, interior lights, and the alarm system.  If your windows are acting up, I'd start there, but I would also check the central locking and alarm box under the seat, it often gets wet and causes no end of issues.

[joecal]

Thanks for the reply, I appreciate it. I had the CLU box repaired and it was still blowing the C3 fuse, so I wonder if I damaged it. The windows went down fine so I think the motors are okay, they just won't come back up. The fuse is good and the top and interior lights are working which are on that same circuit. Hopefully once I get it sorted out it will be fine, it runs and rides nice but so far it's been a very frustrating experience.

[JFP in PA]

Thanks for the reply, I appreciate it. I had the CLU box repaired and it was still blowing the C3 fuse, so I wonder if I damaged it. The windows went down fine so I think the motors are okay, they just won't come back up. The fuse is good and the top and interior lights are working which are on that same circuit. Hopefully once I get it sorted out it will be fine, it runs and rides nice but so far it's been a very frustrating experience.

 

Well, as you have posted on other websites that the fuse does not blow when the replacement central locking system/alarm controller is unplugged, I'd start with that.

[joecal]

I agree, I'll probably take the CLU out and send it back to the company that replaced it and have it tested to see if it's still good. The top and the interior lights work now, it's just the windows won't go up and the key fob doesn't work which it didn't when I bought the car. I can live with opening the doors with the key but I need the windows working obviously. I'm in the process of installing a new top so at least I can finish doing that hopefully next weekend. I hope that turns out alright!

[joecal]

Hi guys just an update on the windows, they are both working. It must have been a switch in the rear for the convertible top. I raised and lowered the roof and both windows started to work again. So I don't think I did any damage using the wrong amperage fuse briefly. Thanks for all your help, I really appreciate it, you guys are Great!!!!!