I recently purchased an engine wiring harness for my 69' 350 firebird but I can't for the life of me get the old one off, (where it connects to the fusebox). Can anyone please help? Is there a certain trick to it? Also, the reason I purchased it was because since restoring the car I have gone through 4 starters, 2 alternators and almost every other elictrical part you can imagine, though I may have missed one... anyway heres whats happening... It used to be when I would drive it at night and turn on my signal the whole car would shut off, and then if you would go to start it, it wouldn't do anything when you turned the ignition on (no electric to any part of the car...) but if you wait about 5 - 10 mins it would work again... Also the ignition switch all of a sudden stopped working so I had to make my own... I took it to the shop and they said that the bright light switch would ground out when you hit it... so they replaced that and the regular light switch. So now it doesn't stop when your driving at night and use the signal or anything else. However I have ran across the problem of when its running and you shut it off somtimes it wont start for 5 - 10 mins again, but it doesnt shut it self off this time. I also noticed that I tried to test the alternator by disconnecting one of the battery cables while the car is running and the car shuts off, thats why I bought the wiring harness, I know its not the alternator (this one is brand new) and I don't think it is the voltage regulator because that was purchased new not to long ago as well. but it seems like when it doesn't feel like starting its almost as if the electrical system overheated and needs to cool off. Does anyone know what could be causing the alternator not to appear to be working properly and what might be causing the other misc. electrical problems? I would appreciate any input. thank you

I had the same problem 2 yrs ago w my 69....some former owner had really butchered up the wiring harness , patched it badly , but I got hold of a good used harness for $50...and installed...but I remember the fuse box being part of the harness, at least thats what I got...
If not you should remove the fuse box whgere its attached , re-place wiring onto it and then re-install the harness and box...lots easier than trying to reattach way under the dash..
Bjorn

I just replaced the engine harness on my 69 350 firebird. To remove the harness you need to remove the bolt from the center of the engine and lighting plug on the drivers side firewall and remove both, then the two should slide apart. Install it in the reverse way. Pete

Well, when i pulled the engine harness off my 400(which i would think isnt all that different from at 350) all i had to do to remove it from the fuse block was remove the single bolt in the middle of the fuse block on the firewall, and both the engine and forward light harness came right out...maybe im thinking of the wrong thing tho