2008 Mustang GT Headunit/Gauge installation problem

smoke4170 · 10-04-2009

Ok guys(and girls), this is driving me absolutely crazy!

I bought a new headunit a few days ago, and in the process of installing it, I seem to not be able to find an "Ignition" controlled fuse or wire!? The HU will not turn on if the wires on the harness are properly matched up, but if I put the "ACC"(red) wire with the constant 12V(yellow) wire, the unit powers right up but WON'T turn off with the key being turned off. So I go buy an "Add-a-Fuse" and try plugging it into one of the empty fuse spaces in the kick panel and connecting that to the "ACC" wire, as I have read past posts that a few of the empty slots are constant power(which I did verify with a test light, always on with key on or off) and a few that are "ignition" controlled(which I CANNOT FIND!!) , but nothing works!!! Now I have done more than my fair share of audio installs in my day and have NEVER ran across this problem! It's totally stumping me.

So I'm left with taking my car down to the local car audio shop and let them mess with it, for probably something really easy or stupid. On top of that, I just ordered new gauges last night and am kinda worried that I won't be able to get them working properly without a switched ignition source for power. Any and ALL suggestions are appreciated, thanx!

10/05gt · 10-04-2009

Wire #687 is Gray with a yellow stripe. It is fused by a 5amp fuse at location F2.6 in the SJB. This wire is hot in run or accessory and is in the wire harness that goes to the OEM radio.

Wire #797 is light green with a violet stripe. It is fused by a 20amp fuse at location F1.56 in the main fuse box. This wire is hot at all times and is in the wire harness to the OEM radio.

Didn't you get an adapter plug with your unit? I have a Kenwood head unit and a 10 disc changer and it was a plug in.

Jezzaaa · 10-16-2009

Quote:

Originally Posted by 10/05gt

Wire #687 is Gray with a yellow stripe. It is fused by a 5amp fuse at location F2.6 in the SJB. This wire is hot in run or accessory and is in the wire harness that goes to the OEM radio.

Wire #797 is light green with a violet stripe. It is fused by a 20amp fuse at location F1.56 in the main fuse box. This wire is hot at all times and is in the wire harness to the OEM radio.

Didn't you get an adapter plug with your unit? I have a Kenwood head unit and a 10 disc changer and it was a plug in.

Hi 10/05GT...smoke and I are having the same problem...and it seems to be with the latest incarnation of the S197....Smoke's is 2008 and mines a 2009.

THat first wire you mentioned ... #797 ... which one of the three OEM radio sockets would you expect that to be in? I know it won't be J4 cos that's the Shaker amp connections. And having looked closely at the J1 connector (the biggest one!) it only has three wires other than the speaker connectors. Two of those wires are the battery live (constant hot) and the other is the earth. The third one doesn't register on a voltmeter regardless of the ignition being on or not.

So would it be in J3 connector (the one the aftermarket harnesses don't use)?

Cheers,
J.

10/05gt · 10-16-2009

According to the wiring diagram. Connector C290d (tan color) is a 24 pin connector. pin 1 wire 797 (lg/vt) hot at all times. pin 2 wire 687 (gy/ye) hot in run or accessory. pin 15 is wire 1000 (rd/bk) and it is voltage in start only. The rest of the wires, pin 8,9,10,11,12,21,22,23 are speaker wires. pin 13 wire 1204 (bk/og) is audio grounding.

Pull up the online wiring diagram so you can see what the connector looks like.

I'm sure there are some changes from 05 to 09 but Ford keeps the wiring harnesses basically the same from year to year and even model to model.

Jezzaaa · 10-16-2009

Hi again...can you explain the Accessory mode? Is that what makes the OEM radio continue to play when the engine is switched off, but turn off when the door is opened?

Cheers,
J.

10/05gt · 10-16-2009

Quote:

Originally Posted by Jezzaaa

Hi again...can you explain the Accessory mode? Is that what makes the OEM radio continue to play when the engine is switched off, but turn off when the door is opened?

Cheers,
J.

Accessory mode is the first key position before run.

The radio and power windows stays hot after the key is turned off because of a timer relay in the SJB. It will run for 5 minutes I believe. The door switches will cancel that signal once a door is opened.

If your having trouble with your aftermarket radio make sure the unit ground wire is connected with the audio ground. Wire 1204 (bk/or) pin position 13