91 HU "SYS" Issue
Thread Starter
7th Gear
Joined: May 2004
Posts: 7
Likes: 0
From: Leesburg VA
91 HU "SYS" Issue
Greets All,
I am experiencing the infamous aftermarket radio HU “SYS” issue in a 91 nonBose system. I have poured all over the site to find the sticky that refers to the schematic detailing the “how-to” fix and a nice thread with photos but my issue is that I do not have the OEM front end of the radio wiring harness (HU) and am using an aftermarket GM product which indicates that he dimmer and illumination wires are orange/orange and white. This is where I placed my resistors . . . What are the names of the wires that are to be resistor connected? Although installed, I'm still getting the "SYS". My battery tests fine and I believe that I am missing a simple step. I know that I am close to fixing this issue. Thanks in advance as any advice would be greatly appreciated.
I am experiencing the infamous aftermarket radio HU “SYS” issue in a 91 nonBose system. I have poured all over the site to find the sticky that refers to the schematic detailing the “how-to” fix and a nice thread with photos but my issue is that I do not have the OEM front end of the radio wiring harness (HU) and am using an aftermarket GM product which indicates that he dimmer and illumination wires are orange/orange and white. This is where I placed my resistors . . . What are the names of the wires that are to be resistor connected? Although installed, I'm still getting the "SYS". My battery tests fine and I believe that I am missing a simple step. I know that I am close to fixing this issue. Thanks in advance as any advice would be greatly appreciated.
Last edited by drojt; Jun 28, 2008 at 10:17 AM.
Safety Car
Joined: Jan 2004
Posts: 3,783
Likes: 15
From: Northern California
On my "91" non Bose, I installed the two resistors on the two wires closest to the end of the connector (I can't remember exactly).
I was unsure of which wires looking at the diagram so, I just temporarily connected the resistors to the two wires I thought looked right and then connected the stereo head unit and switched the ignition on. No "SYS" light came on so, I finished the install. I should've taken a couple of pictures.
Here's the wire diagram: http://www.corvetteforum.net/c4/dave8476/index4.shtml
I was unsure of which wires looking at the diagram so, I just temporarily connected the resistors to the two wires I thought looked right and then connected the stereo head unit and switched the ignition on. No "SYS" light came on so, I finished the install. I should've taken a couple of pictures.
Here's the wire diagram: http://www.corvetteforum.net/c4/dave8476/index4.shtml
Last edited by GKK; Jun 28, 2008 at 01:09 PM.
Thread Starter
7th Gear
Joined: May 2004
Posts: 7
Likes: 0
From: Leesburg VA
Thx for the reply. I have studied that diagram but am unable to decipher the cables as they correlate to the aftermarket harness. I know and have isolated the illumination cable but do not know what the second one is for. More webcrawling is in my future..thx again!
