Ok , I will be the first to admit that I have searched and found a gratuitous amount of " this has been covered before but...."
Lets start with some details

Recipient : 86 base model - Has Third brake light, swapped to 3800 SC
Donor : Unknown year - Has trunk blower connections , connecter for right around the fuel fill (unsure of this one)

For those of you who havent tried this : typing "site:fiero.nl fastback swap taillights" can be helpful ( no qualms against cliff and the search , just find this has worked better for my purposes)

Well i have the specific Tail light issue and am going to attempt to use the "jumper" as mentioned in this thread

** jumper thread link **
https://www.fiero.nl/forum/A...110502-2-102026.html ( 1988 Recipient )

Related Links
Pinouts (85-87) W/ Pics
https://www.fiero.nl/forum/Forum2/HTML/121615.html
Dave E Bouys Thread
https://www.fiero.nl/forum/A...130314-2-114144.html
Gm tuners wiring info:
http://www.gmtuners.com/fil...203_C500_pinouts.pdf

Conclusion : Will need to seperate tail lights and turn signals or remove and relocate " J9" pin. ( Untested )
Wish me luck and feel free to chime in

[This message has been edited by CheshireGrin (edited 11-06-2013).]

I would just try plugging it in without the jumper 1st... I've been working on replacing the harness to my mera body which was put onto an 86 frame and after I plugged in the harness to the C500 and grounded it out all my taillights work fine... I've done a couple fastback swaps and the 1st one I had to jump the J9 pin I believe it was to another one... now don't take me on that because its been a couple years since I did a swap as I haven't had a stock bodied fiero in a number of years now.

\but as I said the harness I did on my mera from a notchback to fastback harness was plug and play

[This message has been edited by pontiackid86 (edited 11-06-2013).]

I should have noted that I did plug it in previously and had the common no taillight but working other lights... Will do more testing and report back... Thank you for your help
Ryan