Replacing Fuses

[Ricks911s]

Working on restoration of 76 911s. I understand there is a red fuel relay. But is the fuse in position 1 a blue, 25 amp fuse? There was a red one in there before. Thanks.

[RWebb]

does the owner's manual list a value?

do not use a bigger fuse than is called for -- unless you want to risk a fire

[RickM]

This may help....please verify....

Help with Carrera 3.2L fuses!

[boyt911sc]

Rick,

Fuse #1 is rated only as 16 amp as per Bentley manual (Table a. '78-'80SC).

Fuses #2,#3, #4------------rated @ 5 amperes.

Fuses #5, #6, #7, #8------rated @ 8 amperes.

Make sure that you follow the correct replacement fuses or take the risk of over heating the circuit. HTH.

Tony

[Jim Sims]

Note that fuse values and locations may have changed from year to year so the Bentley information may not apply to a 1976 911S. I will look in my '76 911S owners manual and post a reply this evening.

[Ricks911s]

Thanks Jim. After looking at RickM's reply, I am reaffirmed of my uncertainty - my position 1 fuse states on the inside of the cover it is used for the fuel pump (separate from the red fuel relay). Look forward to your response.

[boyt911sc]

Originally Posted by Ricks911s

Thanks Jim. After looking at RickM's reply, I am reaffirmed of my uncertainty - my position 1 fuse states on the inside of the cover it is used for the fuel pump (separate from the red fuel relay). Look forward to your response.

The fuse orientation in RickM's attached picture is in reverse order as commonly referred too. Fuse #1 is closest to the front of the car and goes up to S21 for the front fuse panel. HTH.

Tony

[Jim Sims]

Some background information:

The fuse numbering system used in the 1976 911S owner's manual (and also in the factory shop manual wiring diagrams) do not agree with the numbers molded into the inside of the plastic fuse panel cover. There is even a paragraph to that effect in the owners manual! However for our discussion we will count from the front of the car: the forward most fuse position being number one, the next one rearward position number two, etc.

Porsche changed fuse positions from year to year and apparently did not always wait until a model year change over to make the transition.

Therefore for a 1976 model year 911S, the fuel pump fuse can be in either position 16 or position 21; in either case the fuse value should be 16 amps (red color). My car, a 1976 911S without power windows, has the fuel pump fuse in position 16. My front fuse panel has only 18 positions; positions 19-21 were never installed (but there is a space and threaded mounting holes for them on the fuse panel base plate).

If your front fuse panel has 21 positions then the fuel pump fuse is likely in position 21 (red 16 amp fuse) and if your car has power windows then they are likely powered off fuse position 16 through a blue 25 amp fuse.

If you want to check the circuits, remove the fuses in question (16 or 21) and the red fuel pump relay. The fuse clip providing power to the fuel pump relay should connect directly (have electrical continuity) to the rubber relay base hole for pin 87a (look for the pin numbers on the bottom of the relay).

Clear as mud?

[Ricks911s]

Clear as mud. Period. I have 18 positions. Which means I think you might have helped me with a larger problem -- and may require a complete look through on whether each fuse matches its appropriate ampage (sp?).

My owner's manual is in tatters. I know the Bentley is recommended. But Jim, is there anything more comprehensive for the '76? Or is it a piecemeal sort of thing (which is okay -- this is the reason pelicanparts forums are so useful).

Thanks to all - especially Jim.

[tadink]

sorry to revive an ancient thread - but I've also got a 1976 fuse panel and no owner's manual! So I'm not sure what is going where - is there a place to find info on the 76 model year cars? My elec layout has 3 relays (one is red), and the fuse panel itself is an 18 pole arrangement.

I'm chasing down a horn issue - there is clicking at the relay when I press the horn button, but no noise from the flutes.....thought I'd start at the fuse panel (!) and I'm flying blind! My further complication is that the car has been converted to a 3.2L 1989 power plant - and I'm not sure what was done to the fuse panel to accommodate that! ugh.

thx

td