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Hi everyone. I am replacing my engine harness on my early build '77. I did a search and found the following thread. It was a little different problem but had an interesting similarity. The OP in the following thread also had blue and green wires going from the harness to the starter. I have the new harness (LectricLimited) and the 1977 Electrical Troubleshooting Manual and they both show red to the starter.
Engine removed with bolt through where starter was. Battery disconnected.
The blue wire goes into the harness and I will investigate if it has been spliced in the harness in a few minutes. My question is about the green wire. This wire goes directly from the starter to the alternator; no fuse or fusable link. I am pretty sure that is not correct, but now I am worried about some other electrical problem that putting in the new harness will uncover.... Why would someone put an additional wire from the starter to the alternator? Obviously, bubba does strange things, is probably the answer, but what should I be looking for as I install the new harness? Last thing I need is to be chasing electrical problems around.
For background, all systems worked before I took out the engine except the A/C is removed (heater fan works in all speeds) and the alarm system never worked. Not worried about either of those, but worried about what that "fix" is hiding.
Yes the green wire is definitely not factory. But then you have the electrical troubleshooting manual .
So you know that. The original wire from the alternator went to a plastic Junction block under the master cylinder. If this Junction block of all the main power wires gets corroded, it makes a poor connection which causes heat. Which makes the plastic Junction block melt. (Ask me how I know).
So highly likely someone ran a new charge wire to bypass some old corroded connections.
your about to put in a new harness, don't worry about it.
Now if your running a higher output alternator than stock. Worry about it.
(Do it right).
Thanks 4-Vettes. I am updating my alternator for electric fans and electric headlight motors so I would like to get this right. I ordered a 150 amp alternator to replace the current one. I replaced the engine harness and in the process cleaned up the contacts at the fuse block for both engine and front lights harness' as best I could. Hopefully that helps everything else that I am going to do. So I sketched out what I am thinking based on @Richard454 recommendations in another thread. Should I install the wire from the starter to the bus block as below (and how it is currently in the car)? If so, what gauge and should it be fused? I think 8 gauge and a 50 amp fuse?
I realize that the amp and sub don't need a 150 amp fuse, but that circuit is fused already and I figure I will have an extra 150 amp fuse if needed and I would drive home without music.
Please let me know if my logic is wrong or I need to address something else.
As you know, I also have a early 77. Headlight relays, 140 amp 3 wire alternator, twin electric (C5) fans. Upgraded Air-con with C4 blower motor. Electronic fuel injection with a constantly running fuel pump.
So, some similar needs as to your car.
I don't run a fancy stereo with a high power amp.
But still, similar.
What I did, motorcycle type battery cable, (Think Harley not moped). To a strip fuse panel mounted on forward face of passengers footwell. I'll look and see if I have an old photo. Anyway, 100 amp strip fuse to Alternator, 4 guage wire then to Alternator. 50 amp strip fuse to electric fan relays. 30 amp fuse to Headlight relays. In the battery box a single strip fuse for EFI and my DUI distributor with power wire and ground wire run with battery cable under the floor 6 guage. I believe strongly in going heavier in wire size than some might think is OK. lots of heat in C3 engine compartments.
By putting the fuse panel less than a foot from the starter solenoid and using a cable near the size of the cars main cable I feel relatively safe.
I dug, found these,
Fuse panel with cover on.
Note that the Motorcycle type cable is zip tied to the main positive battery cable. 3 strip type fuses for higher output alternator, headlights and fans. EFI requires clean power off the battery so separate heavy guage wiring run from battery compartment to relays on the firewall.
So, sort of like your drawing, only I have EFI off the battery instead of a amp. And a fuse panel instead of a simple bus bar.
These strip fuses work extremely well in the high heat environment they are located in.
Well, I finally got it back together and running and I thought I would let you all know where I ended up. I ended up with a fusion of the ideas from 4-Vettes and Richard. Thank you both for your recommendations, pics, and figures. I replaced the engine harness but not the front lighting harness. The lighting harness may be a next winter project as it is okay but seen some better days.
For those thinking of something like this it is not too bad (well, with the engine removed!) and I had not really done any electrical work before. The biggest thing is to take is slow and really check everything before hooking up power. I made one change, double checked, hooked up the battery to make sure it all worked and then went on to the next thing. This way, if something went wrong, I could easily figure out what I did. Worked well for me.
So far so good. Hooked back up and running and no blown fuses/car fires/burning smells and things work way better than before. I cleaned up any grounds that I could and reattached as I went along. I will say that the starter sounds MUCH better than it did, the voltage meter is rock solid with new electric cooling fans and Richards electric headlight motor conversion (really nice kit by the way!). Very happy with the outcome.
1977 Engine Wiring Harness Replacement
