Novice Question - what is this?

[BC12D]

I am a first time Porsche owner of a 1980 911SC. On the left side of the engine compartment is this component with a heat damaged wire. What was it’s function?

[Synchro Joe]

You can find some basic info here, the lower part of the fuse diagram shows the small fuse block wiring :
Fuse diagram

[BOPE]

There are two fuse holders in the location shown in your pic and one is supposed to hold a fuse for a blower motor located in the upper left side of the engine.

Sorry, I can't recall what the other fuse is for.

Jason

[wazzz]

Upper fuse (missing on pic) is fuse 24. It is a 25A fuse. Its output should be a 1.5 gauge red/black wire going to pin 30 of defogger relay. Its input is a hidden connection inside the plastic holder. So it is normal to have no wire connected to it. It gets its input from the next fuse which is middle fuse.

Middle fuse (missing on pic) is fuse 23. Again a 25A fuse. Input is a 2.5 red wire. Beware, this is permanent power. Disconnect battery if working on this circuit. Its output should be a red/white 1.5 gauge wire going to pin 30 of heater blower relay.

Lower fuse is fuse 22. It is a 5A fuse. Its input is a 1.5 gauge red wire. This is switched power. Only hot when ignition is on. Its output should be a small (0.5 gauge) red/black wire going to pin 86 of heater blower relay.

All this is from my reading of Porsche factory diagrams. Hope they are correct.

[BC12D]

Thanks for the information. I now have a service manual that I have been studying and need to find someone locally who is experienced and enjoys working on a 35 year old 911 that has been sitting for 20.

[HarryD]

Originally Posted by BC12D

Thanks for the information. I now have a service manual that I have been studying and need to find someone locally who is experienced and enjoys working on a 35 year old 911 that has been sitting for 20.

Where are you located? A fellow Pelican may be able to recommend a shop. Also, local PCA chapter may be of help.

[76FJ55]

Looking at the picture, it appears to me that this damage is localized heat damage. most likely due to a pour connection of that wire to the fuse holder block, but possibly due to a bad connection between the fuse (not currently installed) in the middle position.

if this was an over current issue the full length of the wire would have heated up and so the lenhht of the insulation would be damaged, but that is not the case with your wire. you can see that the end connected to the fuse block is completely discolored and black however as you move away from the fuse block the damage condition greatly improves and only a few mms from the connections the casing looks completely fine.

disconnect your battery first, then remove this wire from the fuse block and fully clean it and the fuse block connector. DeOxit is a fantastic electrical cleaner.