Quick question: where does this pink wire go?
 

The pink wire in the upper right corner with its own grommet?
I have a hole in my firewall and no wire...
The picture is borrowed from another thread I was reading this morning while trying to find answers to other missing/misplaced wires.

Thank you.

Re: Quick question: where does this pink wire go?
 

If it is a 1970, then it is for the TCS(Transmission Controlled Spark) relay power. The one end plugs into the fuse block under the dash. The other end plugs into the TCS relay. The relay is screwed to the firewall edge to the right of the HVAC box as shown below.

https://67-72chevytrucks.com/vboard/...1&d=1353985035

Re: Quick question: where does this pink wire go?
 

It might also be for a TH400 kickdown switch.

Re: Quick question: where does this pink wire go?
 

Ok that makes sense now.
My truck, when I first got it, had the funky relay mounted right beside the heater housing...and I do have a t400 transmission.

So I can safely remove this connector from the fuse block inside the truck to clean it up a bit?

I was also going to remove the cloth/bootlace wire from the fuse block on the front of the firewall, and connect a new wire that would be the switched power/trigger wire for the relay I have which sends power to a strip of connections. (Fuel pump trigger wire, electric fan trigger wire, MSD switched power, electric kick down on transmission, etc)

Re: Quick question: where does this pink wire go?
 

Green wire in the bottom picture is the temperature sender wire....it is cracked, so I may as well run a new wire for it too.

Re: Quick question: where does this pink wire go?
 

Lol, found the connection of wires I needed to find in my scrap pile.
Shows the cloth/bootlace wire connected to the two yellow wires that go to the starter and coil.

Re: Quick question: where does this pink wire go?
 

That white cloth-covered wire is the resistor wire used for the coil power in a points distributor. On the other side of the firewall that position connects to the 12 gauge pink wire, which is unfused switched ignition power. It should be OK to put those switched devices under the hood that you mention on power that comes from that position. I suggest use 12 gauge pink wire for that. The wire and devices would be protected only by the fusible link at the battery unless you added an inline circuit breaker or fuse, or a small fuse block somewhere. I bought a ready-made pink wire with terminal that inserts into the firewall connector, having an HEI power plug on the other end, from Year One. At some point I may tidy up my wiring by tapping into that wire to connect the kickdown switch and electric choke. As it is right now I'm using that pink wire with its own grommet that you mentioned at the top of the thread for power to my electric choke, and kickdown is not yet connected.
https://67-72chevytrucks.com/vboard/...1&d=1465078686

Re: Quick question: where does this pink wire go?
 

....aaaand I've added yet another note to my pdf wiring diagram, thanks ;-)

Re: Quick question: where does this pink wire go?
 

I do believe it was your picture I used in my first post of this thread. Thank you for that.
Yes, there is another pink wire that is plugged into the “infused” terminal on the inside cab fuse box.
I have removed that as well, because I bought the 0-8K rpm tach dash from Brother’s Truck about a year ago, and am just getting around to installing it. (Way too many changes over the last year.)
Anyways, the harness that came with the new tach dash, has the same double connector end on it as the original wiring harness that was plugged into the fuse box.
I was looking up the MSD 6-AL2 wiring, to see if I could just connect the factory tach coil neg. wire to the MSD grey tach wire. Not sure if it will work, as the factory tach uses the pink wire as the positive, and the other wire connects to the factory/stock coil “-“ post, while the MSD has the grey tach wire, but it’s a square wave 12 volt signal, so a tach adapter may be required.

Re: Quick question: where does this pink wire go?
 

Tach compatible list...says to bypass in line filter.
I don’t think I have any type of filter installed anymore....

Re: Quick question: where does this pink wire go?
 

Searched and read a few threads on hooking up an MSD to the factory tach, and they all pretty much said, just hook the grey MSD tach wire to the factory tach wire. (Brown in this case.)

I had an Autometer tach before this factory tach dash, and it worked fine straight to the grey wire.

Re: Quick question: where does this pink wire go?
 

Yes, I'll bet you're right. I have electric experience but don't specifically have tach or MSD experience, and a quick search of the forum finds threads where people discussed connecting tach to the MSD grey wire but I didn't see any threads that had the original poster saying "tried that and it worked." I suggest contact MSD, Brothers, and search threads, and if you try something and can't get it to work, post a new thread in the electrical section or this section of the forum and see what people who've done it say. I'll bet there's a ton of people with some sort of MSD and tach. Regarding the orange highlighted line, I think you don't really have GM, you have MSD and it's a different animal. But it probably doesn't need a filter. The factory GM or HEI setup are sort of like square waves, but noisy with spikes. MSD may produce a tach output that is too clean. It will be interesting to hear your results.

Re: Quick question: where does this pink wire go?
 

Do you have a kickdown switch for your TH400? Maybe you need that lone pink wire through the firewall.

Re: Quick question: where does this pink wire go?
 

I am using a LOKAR electric kickdown now.

Re: Quick question: where does this pink wire go?
 

Do you happen to have a part number for that wire handy? :)

Gary

Re: Quick question: where does this pink wire go?
 

Yes, click on the picture of the wire and it takes you to my thread and right there I have the link to year one. Their part number is L00510.

Re: Quick question: where does this pink wire go?
 

Thank you! :metal:

Gary