In Need of Wiring help!!!

78targa · 78targa's Garage

Alright guys,

I am stumped and know that one of you can help. I am putting back together a 78 Targa and have gotten into the under dash wiring. I have found several cut wires and cannot figure out what they are supposed to go to. Apparently someone got under the dash and did a butcher job when they installed a radio and possibly an alarm system (not me!). I am trying to figure out in particular several wires that come out of the sixfold cable connector attached to the fresh air blower switch. The good news, I have a full set of shop manuals, the bad all of the wiring diagrams got wet some time ago and I can only open the dang things partway (I can see the blower switch diagram).
What I need help looking for:

1) What does the brown and white wire attach to? (it is cut clean 3 inches after the plug) It doesn't Ohm out as a ground and when the ignition is on I am getting .2 volts.
2) What does the black wire connect to? It is not a ground and with the ignition on it reads around 12 volts. Might this be for the radio?
3) The yellow and red wire coming off of the blower switch is cut about three inches from the solder joint. Looking at the schematic it should connect to the blower switch light. I do not believe I have one of those as I thought it would be to the right of the fan lever and I have a the lens spot filled with a tab that says "fan". (note the cigarette lighter works, well sort of)

Might as well throw this one in too:
4) Yellow wire coming off of the ignition bundled with a black and blue wire. reads 12 volts with the ignition on. I think it is for the radio, but then what about that black wire???

I am going nuts here. There is a lot more to trouble shoot, but I figured I should get these all hooked up (if they are supposed to) before tackling the defroster light and the emergency brake to name a few. Are some of these wires not needed? If they are what are they for??? Any help would be appreciated!

78targa · 78targa's Garage

Anyone, anyone, Beuler... Beuler.

Jim Sims · 01-07-2002, 04:17 PM

http://www.pelicanparts.com/911/911_Parts/Electrical/911_electrical_82SC_Part4-1.jpg

http://www.pelicanparts.com/911/911_Parts/Electrical/911_electrical_82SC_Part3-2.jpg

Although the above are for an 82SC they are likely similar. You need to clarify which side of the 6-fold connector (Tsub6h) the wires are cut; blower switch side or blower side? Yellow wire off ignition is for radio. Your brown and white wire may actually be the green and white one which powers the first(?) fan speed position; check the colors in good light. I believe black wire off 6-fold connector (Tsub6h) goes to cig. lighter and blue wire goes to fuse position 13. '78 may be different though.

Jim

Jim Sims · 01-07-2002, 05:21 PM

Sometime between '77 and '81 this section of wiring changed slightly; the blue wire going to fuse position 13 (82 wiring diagram) was a black wire going to fuse position 15 in 1977. I don't have the '78 wiring diagram. It also appears the yellow and red wire should go to the light bulb; the letters "FAN" are likely translucent and will show light from behind.

Jim

78targa · 78targa's Garage

The cuts are all under the dash and on the blower switch side. I am sure of the color of the brown and white wire. There are 5 wires total coming out of the six-fold connector: white/green, white/yellow, white, black and brown/white. The blower switch functions correctly with 5 wires attached: white/green, white/yellow, white, brown (ground from ground hub) and the yellw/red wire that is cut.

Looking at the 78 diagram I can see that the yellow/red wire is supposed to go to the sixfold connector with an indicator light in-line. It looks like it then turns blue with an offshoot of black (to lighter) once it passes through to the trunk side of the fire wall. That is part of my confusion, because there is no sign the yellow/red wire ever was connected to that connector.

Ack!

Thanks for the yellow wire info, Jim. One down. Anyone else? Thanks a bunch. I know this may not be the fun stuff to answer, but I was really hoping someone likes chasing all of these colored wires all through their car! HA!

Jim Sims · 01-07-2002, 05:51 PM

The brown and white wire is a mystery; circuit traces 60 and 61 are the only one associated with Tsub6h in 1977. I seem to recall the light bulb being in an independent socket with two wires (both red and white) coming out of it; one of these wires should have gone to the 6-fold connector (Tsub6h); any chance the brown and white is faded red and yellow? The other wire from this light bulb socket, also red and white, should have been hard connected (the solder joint?) to the blower switch; this soldered wire doesn't go through the 6-fold connector (Tsub6h). The light bulb socket may still be plugged into the back of the switch panel with severed wires hanging from it; its hard to get access to it. It also may have vibrated out and hung down by the two wires and was then summarily cut off by both wires.

Jim

Roland Kunz · 01-08-2002, 06:42 AM

Hello

Brown is allways ground

White is normaly use with the light but on the blower it is one stage for the resistor cascade.

78 maybe still has the unneeded wire for the gas heater.

Grüsse

78targa · 78targa's Garage

Roland,

Good point about the brown/white wire potentially being a ground. As the schematic for 78 fails to show a ground to the fan indicator light, maybe the brown/white was used for this light. Dunno. That .2 volt reading I get from it doesn't sound good then. I do see a brown/white wire going to a current track around 47. Unfortunately this is where the pages have welded together.
As for the black wire, would it be a ground as well? It doesn't go to the cigarette lighter and I found a nub of a connector with a bit of black wire left attached to the ground hub under the dash. Of course maybe it was cut because it was grounding out the circuit.

Full circle.
I think at this point I need to pull everything from the boot side of the firewall and trace them out. If anyone else has any ideas please let me know. Could these have been part of an alarm system?

Roland Kunz · 01-10-2002, 08:05 PM

Hello

Sorry hadn´t time to look after your problem ( maybe over the weekend ) but if the brown wire has a additional color code then it is a switched ground.

Black is normaly ignition or hot in a other way but some guys use black wires for everything also other car manufatorers ( Ferrari, Fiat, Volvo or Brits ) use the colors in a other way.

Grüsse