Parawhore

When I bought my '84 944 I noticed that the PO had a complete aftermarket Alpine stereo system installed "Professionally" (Not even close). However, the stereo is wired up to come on when the key is in the "ON" position as opposed to the factory accessory position (Key just in the ignition, not turned).

I dug further into it and realized he had wired entirely new wiring, with more modern inline fuses and torn all the old wiring right out.

My main question is, what else in the vehicle is turned on when the key is in the "ON" position, engine not running? I regularly go to the drive-in up here and would love to take the 944, but don't want to kill the battery. I do plan on ripping out the hack-job stereo wiring that is in there and re-wiring it all myself eventually.

My other question is, where would the factory stereo power and switched wire have gone to from the stereo? Ideally I want to re-wire it to the factory location. But for all I know the accessory switch might not even work. I noticed the sunroof doesn't release when in the accessory position.

I love electrical, oh so much...

veleno

How about some pictures of the wiring so we know exactly what you're talking about?

Is there just new wiring at the head unit or did the PO replace all the OEM wiring with new wiring?

You can find the "acc" power by using a test light with the ignition switched to "acc"

Parawhore

The new wiring seems to just be for the stereo itself. He has a ground wiring going up into the dashboard somewhere behind the glove box, and the power and switched wires both going to in behind the fuse box somewhere. The entire fuse panel itself is OEM, but he wired a small secondary fuse panel in with three fuses strictly for the stereo system.

veleno

Sounds a little overkill for a stereo (and a lot more difficult to change a blown fuse) but the PO had their reasons for doing what they did.

For the ground, see if it leads to the battery area. They may have wired the ground to the battery ground bolt on the engine firewall.

For the extra fuse panel, what wires do they connect to on the stereo side?

Test the switched and power wires to see if either of them have 12v with the car turned off. If they don't, see which wire has 12v when the ignition is turned to acc. Do the same when the ignition is turned to on.

Since the original wiring (or harness) is still there, when the ignition is turned to acc, test the wires to see which has 12v. Double check to make sure it only has power when the ignition is turned to acc and on (do this by turning the ignition to off or removing the key). Once you find the wire you can rewire your head unit with that wire so it only turns on when in acc or on.

Parawhore

Veleno, I took your advice and I tested a few of the wires that were just cut at the back of the dashboard. I found the original switched power wire for the stereo behind the glove box. It seemed to loop around the dash and go in and out of a couple of relays. But the switched wire is now back to the factory circuit.

The stereo seemed to be grounded to a bolt behind the dashboard and it was what was causing the stereo to go into protect mode every now and then. I re-wired that to a solid body ground.

I left the 12v power wire that the PO had installed. The original runs into the factory clock and then loops back to the harness. It seemed fairly thin and decayed so I figured the newer wiring should be good for that.

It looks like I've gotten everything sorted out back to where it should be. Thanks for the help!

veleno

Glad to hear everything worked out for you. Post some pictures when you get the chance!

fmartinez1897

The PO for my 88 924S did the exact same thing, Alpine radio. Couldn't turn it up more than half the volume without the radio turning off. Went to best buy with another Pioneer radio that I had from my old car. They fixed it right up and never had the problem again