basic harness

Working on cutting out all loose wires. I really don't need the extras like a/c, heater, radio. This fuse box is crazy looking. I have the front lights and markers layed out now. The problem i am running into is isolacting the circuits in the fuse box. I have a chilton and the fise box cover, but i neeed to figure out how the under side runs to all the circuits. Is there a diagram or something for this or is it a job for a ohm tester.

Youre dealing with fire under there! I cant see anything that you would gain by taking these wires out but I will try to help you.

Looking at the wiring diagram, find the wire you are trying to remove.

Once you find the specific wire, it will have a designation/pin-out on it; e.g. J23 which, for example, is the power to the fresh air blower motor. J23 means that it is the 23rd pin of the J block under the fuse block (central electric). So, look for the pink and aqua colored plug under the fuse block that says J on it and then look for pin 23. Looking at the schematic, it should be a Black/Red wire (sw/rt means black/red) and as well, the schematic tells you how large the wire is, in this case, it is 2.5mm.

Once you have the wire found, pull the central locking rail to release the plugs and remove the J block to remove that wire.

Tthanks for the explinations, my schematic makes a little more sense. Really i am just trying to clear out alot of dead end wires that are hanging around. I figured i would try and do it right if i can, instead of leaving cut wires every where.

If it only makes a little more sense, I can probably clarify more.

The hardest part is reading the grids. Notice on the schematic, the top row of the grid is letters and the vertical is numbers, if while tracing a wire through the grids ends with a box/diamond with a letter-number like B38, it means go to the sheet that has B on the top row and then go down to the 38th row to pick it back up. This is probably the most confusing.

Beyond that, each wire will either go to a pin of a relay, switch, connector or the fuse panel. Sometimes porsche will not let you trace the wire through a switch especially complex switches but I dont think you need to worry about that.

Please let me know if you have ANY difficulty with this. Its hard to explain in text but I will try.

Issue with relay g19, i cut a couple wires to it by mistake. During research this is for the water pump for turbo cars. I am not finding a relay on my diagram for it,

Theres a two brown wire connection, one goes to E22 the other i do not know.
the middle yellow wire i neeed placement on
Red/yellow i need to know the placement
black/green is connected to E24 with another wire i am not locating on my schematic
red/green is connected to N43

The problem i am having is no power to internals or starter switch. I thought i isolated the front lights and removed the clutter of dead ends in the engine bay. I have power to the fuse box and fuse 11, i checked relay x and it has power. Relay g19 has power to the red/green wire which powers the yellow wire.

I also took out the cruise contorl wiring. According to the schematic, this circuit is an isolated circuit except to the brake and clutch switches

Hmm. Well, this will be difficult.

What you are discribing seems to be G21 not G19. I will try to work from this relay back to the power source. The pins at this relay are:

Pin 2 - Two brown wires. One supplies ground to the turbo water pump motor. The other brown wire goes to E22 of the fuse block (which is a main body ground as well and serves to ground the DME relay at pin 85 of the DME relay).

Pin 4 - Yellow goes to the turbocharger temperature switch at the turbocharger.

Pin 5 - Red/Yellow supplies +12V power to the turbocharger water pump at pin 1 of the motor.

Pin 7 - Black/Green (hang on to your pants) goes to E24 of the fuse block where it then goes to Pin2 of the oxygen sensor as well as to a 15A fuse #34. From here it splits off to F25 of the fuse block to power the fuel pump and as well to pin 87b of the DME relay.

Pin 3 - Red/Green (a big one!!) goes to pin N13 of the fuse block. It then leaves the fuse block at O43 as a Yellow wire but simply returns to the fuse block at J33. From J33 it goes to a 7.5A fuse #7 which recieves main unfused (+12V) power.

Ok thats going to be fun but ill work it out.

In the 86 models it shows G19 to be that relay according to some sites, then for some reason they switched it to the G21 relay later. My box only has the G19. I hate stupid changes, it confuses everything.

Thank you for the information.

I think i need a turbo schematic, the chilton doesnt seem to have turbo wiring in its schematic.

Looking through your description and chading wires, with out the turbo motor in the car the followingcould be deleted;

Pin 2 water pump ground leaving main ground intake
Pin 4
Pin 5
Black/green to the oxygen sensor

Correct? That is how i have it right now

Colin,
Search the internet for the factory 944 Workshop Manual, its 7 volumes and has all the various model electrical schematics. I'm sure I got mine free. If you can't find it, PM your address and I will send you a disc with the zip file.
Mike

cfgioja wrote:Looking through your description and chading wires, with out the turbo motor in the car the followingcould be deleted;

Pin 2 water pump ground leaving main ground intake
Pin 4
Pin 5
Black/green to the oxygen sensor

Correct? That is how i have it right now

Yup.

Ok, i have the engine bay wiring all cleaned up. While looking at the other sections i see some rotted exposed wires, this is not good. Time to clean them up.

Thankbyou 944lt1 for the guidance. I sure ill have more questions.

No problem any time.

Make sure to keep ALL wiring, connectors, etc stored away in case you need them later.
Also, make sure to trace the circuits that youve deleted in you manual for future reference!

I didnt think about the connectors, but i did highlight the connectors i am keeping and using a red pen on the ones i am deleting.

So this harness is coming along just fine now that i understand the schematucs a little better. I am trying to do a little more than just fix the harness but I do not want to jinx my progress so hush on that for now.

The concern i am having is removing the alarm box since i am not running any stock system in the circuit except the voltage gauge. According to the schemtic the alarm box wires to the alternator via blu wire in the two pin connector. Also it has a red/yellow wire that runs to charge control. Originally we just jump this wires on the alarm box pin out. Can i just short cut all this and connect the two wires if the dme relay has been removed so gthe volt meter will read?

In case the dme seems to be an issue, i of course do not have the stock computer installed, cutting out half the need for it. Stock fuel relay system is no longer in use via standalone engine harness, and the compressor and O2 sensors have been deleted.

Money is a issue as for anyone else so trying to do this correctly with out buying aftermarket guages for now.

I had a brain fart while hooking all the wires back together and opened the hazard light connector to figure out why it was not the one for the fog lights. ya i feel stupid.

Anyway I need to know which wire goes to what socket. I tried using the side of the switch for information but the diagram is half missing.

any help would be alwesome.

PIN# and wire colors of Hazard Light Switch

15 - Black/Red
30 - Red/Green (to headlight motor)
31 - Brown (Ground)
49a - Black/White/Green (to flasher relay G4)
49 - Black/Yellow (to flasher relay G4)
58 - Grey and Grey/Blue (2 wire pin)
R - Green (to right side turn signals)
L - Black/Brown (to left side turn signals)

Thank you

Stupid @chilton doesnt show the circuit for fuse 18. Theres a few things running to it, i have unhooked the instrument cluster and still blowing the fuse. I am stuck

Hey Cfgioja,

Try this link to the Porsche 944 manuals, Chilton is incomplete.

http://www.9ss1.dk/porsche944/garage/workshop.html


Mike

thank you for the link, but it looks like the volume ends at air conditioning

Fuse 18 recieves +12v from Pin 87 of G2 relay 15. Then from fuse 18 to the following:

Pin B13 of central electric which supplies power to:
- Pin 5 of plug C of instrument cluster (voltage gauge, oil gauge, brake fluid light, oil pressure light,
various other lights)
- Pin 4 of plug B of instrument cluster (Tachometer)
- Pin 13 of plug B of instrument cluster (Speedometer)
- Pin 4 of plug A of instrument cluster (water temp)

Pin B14 of central electric which supplies power to:
- Pin 1 of speedometer sensor at transmission

Pin B15 of central electric which supplies power to:
- Pin 15 of G18 (lifting roof relay)

I wouldnt go any further with any more mods to the harness... looks like you heading into the more complex part of the electrical system which is harder to read/diagnose. Especially without a proper schematic!

Just my opinion though.

Ya i am done modding the harness just trying to get everything hooked back up. I think i have a bad box too, thers a couple connections that are made in the box that are not showing continuity with my tester, so its a pain.

Just finished talking to the All Data Rep and I am on a week trail of their program, I have used this during school and it helped out a bunch. Currently I am going through the program and printing anything electrical off and crossing my fingers. There schematics already look better then the schematics I have now. Theses are suppose to be unedited from OE documents.

I will let you know how it goes.

well these new schematics worked wonders in 10 mins of understanding how they flowed. I stopped fuse #18 from blowing.

The manual I have showed that there are brown ground wires such as the connectors on the instrument cluster;

A9, A16,etc

It also showed the connector like A4 to be a ground. Well that caused a direct short.

Now I need to figure out what to do with the connectors that join;
A4, B13, B4,C5, and the pinout on the fuse box B13. these are not brown but a combination of black wires. Do these go to a 12v source?