Help with part identification

Naturally aspirated tech and talk
daveaschenck
Posts: 1
Joined: Sun Feb 08, 2026 12:41 pm
Hi - I have an '87 944 NA that I am slowly bringing back to life. I took the car for a 20 ish mile ride on Friday, parked it and got back in it Sunday afternoon for another 20 ish mile ride. On Sunday when I got in, the part in the picture was sitting in the driver footwell on the right side. The car started right up and everything that worked on Friday and still worked and everything that didn't work, still didn't work. I've been under the under the dash for various projects and never noticed any bad wiring (scotch clips, wire nuts, etc.). This doesn't have any solder marks that I can see. Any idea of this should be somewhere or if this is just random?

Thanks,

Dave

1987 Porsche 944 NA
Towson, MD
Add Pictures/Files
IMG_1023.jpeg
IMG_1023.jpeg (1.9 MiB) Viewed 44 times

#1

User avatar
J-Dub
Posts: 665
Joined: Mon Mar 20, 2023 1:24 pm
Location: Phoenix, AZ
Has thanked: 658 times
Been thanked: 568 times
Looks like a 68 Ohm 5% resistor. It likely is just random however someone may have been using that to fix a two speed radiator fan controller function or something similar. I would add it to your parts stash as one day maybe you will need to make a voltage divider circuit.
1957 VW Beetle
2004 VW R32
2021 Porsche Cayman GTS 4.0

#2

chrischrischris
Posts: 134
Joined: Mon Mar 03, 2025 11:10 am
Has thanked: 5 times
Been thanked: 34 times
No idea what that could be from. I installed a resistor to trick my airbag circuit when I removed the airbag steering wheel, but it was a way different value than yours. And I think the 87 NA didn't come with an airbag wheel. So, that's likely not helpful but it's all I got.

#3

User avatar
Tom
Site Admin
Posts: 8975
Joined: Fri Jun 25, 2021 2:04 pm
Location: Silicon Valley, CA
Has thanked: 943 times
Been thanked: 4034 times
Contact:
That’s an important resistor that fell out of the back of your instrument cluster. It sits in parallel with the alternator warning light and is part of the alternator exciter circuit. The resistor provides a current path to the exciter wire even if the bulb burns out, and also adds extra current to help ensure the alternator begins charging reliably.

It plugs into two little individual sockets behind the voltmeter. If you pull your cluster, you should be able to plug it back into place. See pictures below.

I’d take the time to do that to make sure the alternator is working as designed. You might clean the leads with fine sandpaper or the like, and put a few small kinks in the leads so the sockets grip them better and it doesn’t keep falling out. You might also check it with a multimeter before putting it back in, just to make sure it’s still working. If not, you can replace it with another 68 ohm resistor, but be sure it’s rated for at least 5 watts, or 4 watts at the very minimum. It can pass a little over 0.2 amps and dissipate a few watts when the alternator warning circuit is active.

r-in-situ-2.jpg
r-in-situ-2.jpg (199.43 KiB) Viewed 23 times
r-in-situ.jpg
r-in-situ.jpg (93.15 KiB) Viewed 23 times
68ohm.jpg
68ohm.jpg (58.15 KiB) Viewed 23 times

#4

Post Reply