1978 Wiring Harness

[Joseph A.]

Hi everyone!

I'm about to order wiring harness and some harness are first design, courtsey lamp timer located to left of steering coloumn. Or Second design, courtesy lamp timer located to right of glove box. How do I know if I first or second design? All my wiring harness are in a box on a shelf in my garage. What harness should I replace? What does the courtesy lamp timer look like? Can you tell By your VIN if you have first or second design? The harness are all going to be ordered from electric Limited. Any help would be greatly appericated.

Joe

[Tom R.]

Re: 1978 Wiring Harness

Joe:

I suspect you'll find yourself on a Lewsis & Clark expedition here...probably not too many have done a full restoration on a 78 but I may be able to offer some insights that will help.

This is where you'll need your AIM. Page 506 shows the courtesy lamp timer behind the dash on the driver's side. But than you've got to look at the "revision" section at the bottom to see when this sheet was published. It shows the last revision dated Dec 77 which is mid production. It shows View A revised which is the timer view but it also shows it taped to the wiring harness. So before this date IT MAY have been located on the other side or as your describe it as the 1st design.

Now you'll have to figure the build date of your model...look at the trim code date. The VIN will also provide an approximate date if you have the Birthday Book but the trim tag date code is more accurate.

Of course the best action is to trace it on your harness. Start at the fuse box end...this would be the "behind the dash to the left of the steering column" version. The timer comes off the fuse box harness and as stated...tapes to the harness. If your harness does not show it at this end...trace it off the courtesty lamp on the passenger side or the glove box lamp.

But the button line is this...it tapes to the harness and if your model has the B2Z option it doesn't matter what side is mounts on. If your model does not have B2Z...than you won't have the timer option. If you are not sure whether you have B2Z...the easiest factor is the rear courtesy lamp located just above the spare tire carrier. Hope this helps.

[Joseph A.]

Re: 1978 Wiring Harness

Tom:
Thanks for the info. I looked at my dash harness this morning. I found that the time is on the glove box side. Its wiring is right next to the glove box lamp wiring. The timer on my car is orange in color and has a GM part number of 463498. I called my local chevrolet dealer and they told me the part number I give them was to a dome lamp timer(control). So I believe that I have a second design harness. Thanks for the help.

Joe

[Tom R.]

Re: 1978 Wiring Harness

Joe

According to the AIM...463498 is the courtesy lamp timer. Now...their parts manual may show it as such because it controls the timing function for not only the dome but all courtesy lamps.

So I take it then that you do have the ZX2 option (convience option)? Was it taped to the wiring harness at that location?

Can you send a photo?

[Joseph A.]

Re: 1978 Wiring Harness

Tom: I don't know if I have ZX2, Because I can't remember if the lights stayed on or not. But I do have a spare tire light, which leads me to believe I do have ZX2 option. No the timer was not taped to the harness it was just hanging down by the passenger side lower kick panel area. Also I don't know how to post photos on this website! I went out to the garage and looked at the trim plate. My code on the trim plate says: (L03). My judging guide tells me that L03 means August 3rd of 1978 is when the car was built. So more than likely I do have second design wiring in my corvette.

Thanks
Joe

[Joseph A.]

Re: 1978 Wiring Harness

Tom also The timer has a witness mark of ol glue residue that wraps the whole timer. So at one time it was taped to something!!

Joe

[Tom R.]

Re: 1978 Wiring Harness

You can send the photo to me direct at

www.hunt4cleanair@earthlink.net