Fuse Problem

CrossT · 03-23-2007, 09:24 AM

Out of the blue, I have a problem with #1 and #2 fused blowing simultaneously. It has happened twice in one week. These are for the windows/sunroof and for the AC. They don't seem to blow while in use, but both times I found them blown when returning to the car after sitting.

Any connection between these or any ideas where to look first?

thanks

todd
86 coupe

CrossT · 03-29-2007, 12:16 PM

I'll respond to my own post, since I have found the issue and others might benefit.

The issue was that the #1 fuse block connections were marginal. Not the wiring, but the posts themselves. I cleaned it up and reconnected things and the problem is gone. I will probably replace that 3 fuse carrier later. I suppose it had built up a level of resistance . . .

As an unexpected side benefit, my windows now function per spec WRT when they will work. Use to be that they [and the snrf] would work any time / all the time. Now they work after the car has been turned off until I open the door at which time they won't work.

I love no-cost fixes.

todd
86 coupe

Porsche_monkey · 03-29-2007, 12:50 PM

I'm going to go out on a limb and guess that you haven't fixed it. There is something else wrong. A marginal electrical connection, even two of them, will not take out two fuses simutaneously in an unattended car.

I hope I'm wrong.

CrossT · 05-03-2007, 10:01 AM

PBH
You weren't wrong . . .
It has continued and seems to be connected to my alarm, which is an aftermarket Clifford unit. If the alarm is off, there is no issue. If it is on, the fuses will blow once a week or so. So far, I've just left it off. I'll troubleshoot it though at some point, cuz I like the remote locking that the alarm provides.

todd
86 coupe

Porsche_monkey · 05-03-2007, 10:13 AM

Confession is good for the soul.

At least you've narrowed it down.

CrossT · 05-03-2007, 12:01 PM

Once again, I am wrong.

Not the alarm, it's something else. Maybe windows, window door switches/relay, AC, don't know.

Out for lunch and they blow again with alarm off. Hmm

I turn the car off and get in the trunk to replace them again and #1 [windows, sunroof] goes in fine, but #2 [AC] heats right up and burns. So, I get in the car and leave #2 out. I drive off and crank down the windows to get some air going and realize that the AC is on and is working as usual! #2 fuse is for the AC and is out.? I return to work and open the door with the car still running. At that point, the AC stops working and the windows won't go up. #1 fuse blew again.

This is too flaky - I'm giving up and taking it to a shop.

thx
todd
86 coupe

Porsche_monkey · 05-03-2007, 12:07 PM

Quote:

Originally posted by CrossT

This is too flaky - I'm giving up and taking it to a shop.

In my mind this is a good reason NOT to take it to a shop. $$

rick-l · 05-03-2007, 01:06 PM

Quote:

Originally posted by CrossT
As an unexpected side benefit, my windows now function per spec WRT when they will work. Use to be that they [and the snrf] would work any time / all the time. Now they work after the car has been turned off until I open the door at which time they won't work.

This is not how the windows are supposed to work.

They should operate with the key on OR the door open.

You don't suppose the alarm is connected to fuse #2 (AC - hot at all times) and the power window control unit (which is connected to fuse #1 and operates when the door is open or the key is on).

Taking it to a shop will definitely be a wallet lightening experience.

CrossT · 05-03-2007, 01:40 PM

I don't know where the alarm is hooked up, but it works fine with both #1/2 fuses blown. I appear to have falsely accused the alarm.

I think the fuse blew when I opened the door, which led me to think of the door light switch, which is also connected to the window relay somehow. I suppose I'll will grab some more fuses and check the door switch when I get home.

Todd
86 coupe

Barrpete · 05-03-2007, 04:10 PM

WOW. I am having a very similar problem. The first time I went to use my AC this year the fuse was....missing! So I replaced the fuse thinking I solved THAT problem. Worked fine for a little while then no AC. Check the fuse & it's not only blown but the plastic part is partially melted! So replace one more time. Nothing. No AC, fuse fine but no power to fan in smugglers box or to compressor. I'm also having intermittent blown fuse problems with the interior lights/radio/clock circuit. Then again sometimes the radio just goes off then after a few minutes it's back on. Usually coinciding with turns or bumps.

I did replace the radio recently so my thought is that there is an intermittent short that is somehow affecting both circuits. Maybe two wires rubbing & after 20 years somehow shorting together? Aggravated by fiddling with the wiring for the radio install?

WKNDRACER · 05-03-2007, 04:29 PM

Make sure you have the correct fuse. A lower amperage fuse will work & will not blow but will melt/burn the wires connected. Just my 2 cents... replace with Glass type. The OEM fuse (specially old) will corrode & cause a resistance. I had a similar problem. I accidentally knocked off the fuse for the fuel pump. It landed inside my extra fuse container. I was foolish to pick up the one that looks the same. They are color coded but I still picked up the wrong fuse. it was 5 amp below specs, "worked" until it melted the wires. HOT!!!!! Check for corrosions (corrosions = resistance)

Barrpete · 05-03-2007, 04:33 PM

Yes it's an easy mistake to make. But it's a 25 amp fuse which is correct.

CrossT · 05-04-2007, 04:20 PM

The odd thing with my situation is that the AC works with the fuse removed from slot #2! I only have a fuse in the #1 slot.

I fiddled with the door switches last night and today the AC and windows worked as they normally do. No blown fuses. I did find that the wires to the compressor were slightly riding on the clutch pulley! Needless to say I re-routed.

These types of things drive you nuts.

todd
86 coupe

Barrpete · 05-04-2007, 04:43 PM

Do you have power seats? They are on the same fuse as the AC & should be inoperable without the fuse.

CrossT · 05-18-2007, 12:21 PM

Seems I've discovered that one of the wiring harnesses going thru the body and then thru the door was split open and [when I opened the door] the wiring was hitting the body. This was augmented by my having no door stay, and the door sometimes opening too wide.

Haven't had any issues for almost 2 weeks now since I remedied that wiring. Now for the door stay . . .

thx
todd
86 coupe

Paulporsche · 05-18-2007, 12:29 PM

At least the wiring issue was a low cost fix.

Porsche_monkey · 05-18-2007, 12:50 PM

You now have my blessing that this is a believable and likely cause of your issues.

Congatulations for a) fixing it and b) admitting I was right. My wife would be unable to do either.

I will consider this issue closed and move on to other pressing Pelican issues that require my sage advice.