Passenger side parking/running lights no workie

[tasturbo86]

1986 turbo.
Passenger side fuse is #19.
With the fuse removed, I only see 10 volts coming to the fuse when the light switch is on.
If I put the fuse in, it drops to about 1 volt?

Driver side, #18, is fine, with 12 volts.
If I take power from #18 and supply it to #19, right and left will work.

Anybody have a WIRING diagram for this circuit?
I can't understand the factory CURRENT flow diagrams.

Lesser problem: Horn doesn't work and the fuse box cover does not show a fuse for the horn.

terry

[pete3799]

The horn uses a round black relay.
Pull the wire out of the fuse holder and check the voltage on just the wire. If not 12V Check voltage at the head light switch.

[kbruz]

I recall that a diode exists in the circuit for the passenger side. It’s up beneath the dash just above the key switch

[kbruz]

Parking light/blown fuse issue

Try this thread

[tasturbo86]

Thanks kbruz, that thread is very interesting!
I also had the rear bumper off recently, so I will check wiring back there.

[86 911 Targa]

^^^^^
This might help.

Best,

Gerry

[tasturbo86]

Gerry,
Where do you get these schematics?
All I have are current flow diagrams, which make no sense to me.

terry

[86 911 Targa]

That schematic is from my factory manual.

pm me if you need help with the diode.

G.

[tasturbo86]

After a bit of probing...

- My license plate lights are ON when the light switch is in the first position out on the switch. Discussion above said the diode should prevent that?

- disconnected the diode and still no right side parking/running lights

- I jumped around the diode and the lights work!

- With this jumper in place, I see 12v at #19 fuse. Before, only 10v was coming from the switch to the fuse panel and it dropped to less than 1v with the fuse is in place.

So, Gerry, aka '86 911 Targa', might be proud of me?
I dragged my multi-meter out and tested the diode.
It reads 0L both ways across the diode (reversing the leads).
According to google, this indicates a bad diode.

Time for a new diode!

[kbruz]

The diode part is no longer available from Porsche. My mechanic just happen to have one in stock so was lucky. About 2 years ago I emailed the manufacturer of the diode (in Austria as I recall) and they were not much help. Could not cross reference to the Porsche part number.

Lastly if you search this forum you will find others have just bypassed the diode with no problem. The odd thing is that the 1987 schematic looks the same as 1986. But the 1986 is the only model year with this component. Not sure why.

[tasturbo86]

I called around and found the replacement part from Porsche.
Actually, you need the diode and the plastic 'holder'.
Diode - 91161710801
Holder - 825971990
Roughly $39 with shipping from https://www.porscheatlantaperimeterparts.com