Early 944 need help on wiring!!

[Aey]

Hi everyone & greetings from Thailand!

I just got this car few months ago and trying to restore everything back to original. The fuse box area is a mess, i.e., few burn/melt wires, some wires are tapped, 2 relays are hanging down, and etc. So today I took off the whole dash and I found 6 more relays behind the dash. I think that’s not how it should be and looking at how the wires were badly tapped, I really need your help to make it right.





Here is the thing I know about this car.
1. Radio has been installed very badly.
2. The front fog light switch has been modified. There is no fog light switch under the oil pressure gauge, but the switch is at 1 of the 4 switches at the ashtray.

These 2 things were done by the same guy, as the same type of wires were used.

I have a basic electrical knowledge and I have early wiring diagram on hand. But looking at the mess, I really don’t know where to start. Anyone has a picture on how the wiring and relay should be? Where is the original & correct location of each relay? Can you please guide me step by step how to check each relay?

Thank you!

[DannoXYZ]

sa wat dee kha!

Those are generic power-relays. Someone didn't want to buy the proper relays to install into the factory relay-box and wired up generic replacements. Best to trace the wires coming out of those relays and draw up a wiring-diagram of what you have.

Then compare it to factory wiring-diagram and match up to what it should be.

Most likely you'll need to remove ALL of that wiring and restore the connection-points between switches, relays and lights/radio/whatever back to stock factory condition. The best and least confusing way to do this is fix one wire at a time. For example, for the fog-lights, start at fog-light switch:

1. find +12v activation power and trace to fog-light switch. Does that wire have proper connection and +12v power? If not, repair or replace as necessary.
2. find +12v switched-power from fog-light switch to fog-light relay. Does that wire send +12v properly to correct fog-light relay terminal? If not, repair or replace as necessary.
3. at fog-light relay, find ground-terminal. Is it connected to ground? R&R as necessary
4. at fog-light relay, find +12v power. Does it get power? If not, check fuse and R&R wiring.
5. at fog-light relay, find +12v switched-power going to fog light. Does it have power when fog-light switch is turned ON? If not, relay may be bad. Test and R&R.
6. trace +12v switched-power wire from fog-light relay going to fog-light. Does it transmit +12v to fog-light? If not, R&R
7. at fog-light, confirm the other terminal is gounded. If not, R&R

Basically, you are checking and tracing every single wire for each circuit shown in the wiring-diagram. Pick a single component, fog-lights, radio, wipers, etc. And trace all the wiring in between those components and check whether they are getting power as needed when switches are in On/Off positions. And the check whether the ground-wires are grounded as shown on diagram.

You want to repair the factory-wiring and restore it to original condition. If a wire is melted from the fuse-box, remove it and replace it with a new wire. Don't just cut it and tap into it to bypass like the previous people. That's just lazy and creates a lot more problems in the future.

The fuse/relay box layout can be found here: 944 FAQ - 13.0 Electrical

and here: Bill's Porsche 944 World: 1983-1985 1/2 fuse panel layout, fuse and relay identification.


Part# for relays I've found, may not match yours exactly:

• 1 Cooling Fan 141 951 253 B
• 2 Fuel pump 993 615 227 01
• 3 Air conditioning 944 615 113 02
• 4 Headlight cleaners *
• 5 Warning time relay with gong (USA) 928 618 102 03
• 5 Catalytic converter monitoring unit (Japan) 911 617 119 00
• 6 Rear window defogger/seat belts 944 615 102 01
• 7 Plug bridge 171 937 545 varies by region
• 8 Additional high beams 141 951 253 B
• 9 Horns 141 951 253 B
• 10 Intermittant wiper action 477 955 531 A
• 11 Flashing turn-signal lights 111 953 227 D

Good luck!

[sausagehacker]

Aey,

I have quite a few of those relays sitting in a box. If you need any, PM me, the ones I don't need are yours for shipping & handling.

[Aey]

Thank you DannoXYZ. This information is very helpful. Yesterday I took a closer look and I found 2 more relays under the dash. Also, none of my relay part# at the fuse box match your :-(

Thanks for the offer sausagehacker. I'll PM you soon.

I'm tracing the wire one by one, and now stuck at the fog light relay. The wiring diagram that I am currently have is missing that part.



Where can I download a complete set of early 944 wiring diagram?

Thank you.

[DannoXYZ]

I've found some diagrams for the foglights. Appears to be 3 variations of non-US wiring. One of these may match yours. The BridgeAdapter determines how the fog-lights work with the headlights (stays on or turns on when using high-beams, etc.).