Fuze problems

[Leland Pate]

Well, although this type of fuze problem isn't nearly as bad as the variety that are plugged into 2000 lb bombs, I am getting frustrated.


I keep blowing two fuses, apparently at the same time.
One is obvious... it's the 16 amp fuse for my window motors.
The other is for my left blinker....can't remember how many amps on that one.
Anyway, they go at the same time, and twice now i've noticed that my blinkers are flashing rapidly and then I try to move the windows.... both blown. And always at the same time.

I replaced it again today and it seems to be working fine, but I have a feeling that it'll do it again in a few days.

I initially thought "the switch is grounding" so I pulled the switches out of the door panels and had a look. All of them were fine. So then I thought.... "relay?" So I tried swapping the window motor relay with another to see if that helps.... Only time will tell.

Has this ever happened to anyone?

Oh,....and we got back safe and sound last night!

[Rick Lee]

I have a recurring and intermittent right front blinker problem. The fuse is 5A and they're not too easy to find. I bought a bunch in a gas station in Germany and have used most of them up already while troubleshooting my problem. This doesn't sound like your problem, but I fixed mine (well, this is how I got the fix to last the longest) by pulling the blinker assembly out and cleaning up the connectors. They need to be spic and span and also very tight. Of course, Porsche does not give you a mm of slack in those wires, so it's no fun. Get some needle nose pliers and a lot of patience. I've heard you can just put a 40A fuse in there and look for where the fire erupts.

[Jim Sims]

Originally posted by Richard LeSchander
I've heard you can just put a 40A fuse in there and look for where the fire erupts.

I do hope you're joking. Over fusing is a good way to end up buying new sections of wiring harness! The wire with the short in the over fused circuit overheats, melts its insulation and the insulation of adjacent wires in the harness bundle causing more shorts and melting. Soon one has many blown fuses, non-working circuits and maybe a real fire. Jim

[CamB]

Leland

I had the power windows blow in the '75. It was due to exposed wiring inside the door, and wasn't apparent until I removed the switches and examined the whole window motor loom.

I think the wires had been incorrectly routed and were being pinched by something and this lead to a portion of the insulation being worn through.

[Early_S_Man]

Lee,

Unless you had a rodent problem near your wiring harness in the past ... I think the two fuses being out at the same time is a coincidence. If you check the fuse block very carefully for corrosion or oxidation at the contact piont where the pointed fuse ends make contact ... and also at the point where the bare wires are compressed by the screw terminals ... brass, tin, & copper can give rise to high-resistance connections at the fuse block, and often the wire insulation is discolored brown from the 'extra' heating at those high-resistance points on the fuse block! If only a few wires are discolored ... those will most likely be at 'troublesome' fuses that blow most often when there is no obvious fault!

It is good to hear from you again, and I hope things are going well with your Dad!

[Leland Pate]

Well, drove to work this morning and both fuses are blown again. The turn signal fuse is a 5 amp fuse.


Man, I just know this is going to be a ***** to resolve.
I will start with cleaning and tightening the connections.

I cannot find those old german fuses at ANY of the local parts stores....

But, at the little shopette on base has nice German fuse kits for our cars.
Today I will buy them out!

[brandett]

Easy to find in Sweden, checked out the manufacturer and viola

www.pudenz.com

seems that they are represented in USA, good luck with the fuze problem.

[HawgRyder]

Leland....
Try looking at the grounding of the problem circuits.
Grounds are the only common theme to multiple circuit fuse blowing.
Something like this can drive you crazy until you finally find it....and then you wonder why it was so difficult.
BTW...I'm off to the glass people this morning to get my front and back windows installed.
I though about doing it myself...then remembered I have no experience in installing glass!
Just getting them out without breaking them was pushing my luck....LOL.
Good luck.
Bob

[targa80]

It sounds like both circuits are being shorted at the same time. I would suggest only putting the 5 amp fuse for the left blinker and drive around with it for a while to see if it blows on its own. if it doesn't then the culprit will be in the power windows circuit. You didn't say when the fuses blow were you using the windows or the directionals or did it just occur on it's own. I don't have the wiring diagrams handy but I would suggest looking at it to see if there is any correlation of the wiring between the two circuits.

[Leland Pate]

Thanks for the leads guys...
I'll play with it this evening and get back with you...

[barlowdo]

LeLand, Are those the only two components wired to those fuses ?

On my '66 each fuse may handle more than one component.

By the way, I feel your pain. I finally got the oil return tubes replaced and installed new Turbo valve covers. Decided to take the car for a spin to see if I fixed most of the oil leaks only to find that I didn't have rear running lites or brake lights.

When I checked the fuse block on fuses 6,7, and 8 all fuses looked good but dirty with corrosion as Warren mentioned above. I cleaned them and promptly had two of them blow and # 6 caused some smoke. I think part of my problem was the corrosion raising resistance above what the fuses were spec'd to handle but... I have found that the running lites to the rear are shorted somehow in the wiring in the back of the car going to the tailights. At least the wires coming the length of the car are good.

The loss of brake lights was just dirty bulb contacts.

Good luck with your Nightmare !

By the way, I am told Autozone has VW fuses which are the same.

-Don

[Early_S_Man]

Don,

Try disconnecting the 6-pin bulkhead connector at the body, then remove the entire taillamp housings for cleaning up of all of the mud, etc. The two-wire pigtail to the oil level sender has to be removed, too, as it is part of the lamp wiring harness!

[Doug Zielke]

Originally posted by Leland Pate

Oh,....and we got back safe and sound last night!

Glad to hear that news, Lee.

And the fuses?
Well, they suck!

[Leland Pate]

Here’s the latest on my electrical gremlin saga.

I did what you guys suggested and tried to determine whether or not the two fuses were related to one another causing them to blow simultaneously or just a coincidence. It appears to be the latter. After two days of staring at wiring diagrams, tracking down harnesses, cleaning connections, yanking the fuse panel, turn signals, right headlight out of the car to test each area with my voltmeter I finally got the turn signals working right.
Other than cleaning all connections and replacing the signal relay, I didn’t do anything. Go figure…

So, now… on to the power windows.

It kept popping the 25 amp fuse whenever I tried to actuate the switch.
Then it just up and died all together…. It didn’t do anything… totally dead. I spent many hours staring at the diagrams trying to figure out what the hell was going on. I removed the relay socket from the fuse panel and started checking everything starting from the battery. I had good ground coming out of the socket… had power to the socket, had power to the fuses (ACC and constant)… That’s when I realized that terminal #87 was grounding out!!!!

CHI CHING!

Unfortunately, I didn’t discover this until AFTER I had fried 4 relays!!!!! I thought I was accidentally putting the same bad relay in over and over…. Nope… it was burning up every single one I put in there….


There’s my problem… but where the short??? I spent another hour pulling the wiring loom out of the mass clump of *^$^*$%^ that is routed nicely under the gas tank inlet hose to try and find a fault. Then I traced it to the inner fender and out to the door jamb.

Cary, you remember harping on me to fix that drivers side door stay???/ Well, it before I fixed it… every time the door swung open, it was crushing the power window wire loom.

So I fixed that and gave it another shot.
Still no go… L

Geez… not I’m really pissed… so as a last resort, I took my volt meter and stuck it in terminal #87 on the relay socket and set it to ohm out… “BEEEEEEEP” I let it ring off while I went around giggling for a short. I unplugged the drivers side door connector…. Which is waaaaay back in where you can barely reach and the ringing stopped! So, I knew the short was in the drivers side… I plugged it back in (started ringing again) and started looking again.
Here’s the kicker. When I put those RS door panels in, I ended up having the panel sit about 1/8” too low on the drivers side, this prevented one of the door switches from fully seating. I intended to get around to it sometime… J
Anyway, what was happening was that the switch was coming free from the door and the back of it was hitting the metal panel of the inner door and grounding out… everytime I pushed on it I Ohmed out… when I pulled it away from the door it was ok.

So, I felt pretty good about myself until I realized I had blown $80 worth of relays trying to track it down!!!

I used my old fuel pump relay to temporarily test it… works fine now…

Well… I guess it was a good learning experience.
I still don’t know if the two were related or not.
Guess I should go ahead and order 5 or 6 new relays…. J

Thanks for all the help guys,

[cary]

Boy, you wouldn't think about it doing that.

Just finished putting the car back together. R/R'd the door panels about 5-6 times. One stupid thing after another.
After all that I ended up with with a short on the window switch also. So I decided after 25 years it was probably time to re- heat shrink the connectors. Good as new.

[pwd72s]

To think, I was about to suggest a conversion to manual wind up windows...welcome back, Lee!

[targa80]

Glad to hear the two problems are solved, To bad it had to be an $80.00 learning experience instead of just being a pain in the butt problem. I always look on these type of problems as ones that are necessary to make you into a better shaddy tree mechanic. Time for a cold pint!

[Early_S_Man]

You know, Paul ... I have yet to blow a fuse in my non-bionic arms!

Glad to hear the mystery was solved, Lee! If you order all 'Red' relays for your spare & replacements ... they will work fine in all applications.

[Leland Pate]

Could'a told me that 15 minutes ago Warren....






************************************************** **************

Here is the information entered for your order:

Name: Leland Pate
Email: leland.pate@mountainhome.af.mil
Phone: 208-794-6072
On-line Order Tracking #
Request Submitted on: Monday, July 29, 2002 at 2:26:27

You have sent a request to purchase:

Item Name Item Price Quantity Item Total
C-615-109-01
Relay, Fog Lamps, Horn, etc., Black round, 911 (1969-89), 914 All (incl Fuel Pump)
$18.75 4 $75.00
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PEL-FUS-8
Fuses, 10-pack, 8 Amp, White, Ceramic
$1.60 1 $1.60
----------------------------------------------------------------------
PEL-FUS-25
Fuses, 10-pack, 25 Amp, Blue, Ceramic
$1.60 1 $1.60
----------------------------------------------------------------------
A-612-333-00
Relay Socket w/Harness
$29.00 1 $29.00
----------------------------------------------------------------------
Subtotal: $107.20
Shipping: $9.88
Taxes: $0.00
Total Price: $117.08



Car Information:
Make: Porsche Model: 911SC
Year: '79 Engine: 3.0L

Additional Comments or Questions:

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I got the relay socket so I can wire so I can wire the oil cooler fan... haven't done that yet.

[Early_S_Man]

It's not too late to call Pelican and make a change ... Lee!