So I installed my PAC SWI-PS in my 5.5 last night. I grounded the BR/W wire to chassis ground, hooked up the resistors to the white PAC wire, and tapped power and ground for the PAC from the wiring harness entering the radio.
After hooking everything up, I programmed it with the radio still sitting outside of the dash. Everything worked flawlessly. I put the radio/bracket onto the “holders” and screwed in one screw. I test it again and the only thing that worked was volume down. I take the screw & bracket out and make sure all the wires are secure. Test the controls again, works like a charm.

It turns out, when I put the first screw in to secure the radio bracket is when things get screwed up. To ghetto-rig this a little, I put the 4 screws through a piece of electrical tape before installing them. Even then, if I tighten them too much, the controls stop working. Unscrew a couple of them ¼ turn, everything works.

I’ve racked my brain and I can’t figure out what is going on here. If it’s any consolation, I’m using a PAC OEM-1 wiring harness for my radio. Granted I run a 5-channel DLS amp, I probably don’t need this particular wiring harness. My radio (AVIC-F90BT) worked as it should and still works as it should.
Any ideas as to why this is happening would be very helpful.

I’d also like to add this is the newest model of the SWI-PS I’m using that integrates phone/Bluetooth compatibility. I like this controller a lot more because the button presses are instant unlike the old version where you have to hold down the seek button to skip songs.

 

give the PAC piece it's own separate ground from the radio. If you hooked up the radio through the harness, the radio grabs ground from the screw securing the brackets to the dashboard.

That said, the PAC piece is resistance-ground based. Thus, when you program the PAC when the radio is sitting outside the dash, its grabbing a weak ground through the antenna, or somewhere else. When you put the radio back in and secure it, a new more solid ground is introduced and screws up the PAC.

Try that see if it works

 

do you think it would be ok to tap it to the same spot as the BR/W wire I have going to chassis ground?

 

sure. as long as there aren't any resistors in between or anything.

 

thanks, i'll do it when I get home. Is this common?

The weird thing is Volume down still works...

 

its makes sense if you change the ground after programming, think about it - you defaulted it to a certain ground, then completely changed it, so its all out of whack when you put it back in the dash. for whatever reason, the resistance for the volume down was unaffected. Each command is a different resistance (for most cars) which is why you only need 1 wire or 2 for all 4-5 buttons.

 

Also, make sure that the resistors that you wired in, are not touching each other. Don't ask me how I know this!

 

you're supposed to wire them into the white wire together...they have to touch each other....

 

Actually, they don't have to. I wired each resistor inline to a piece of 18g wire, and then soldered each 18g wire to the white wire at different spots...no more problems for me! If they are touching, it could cause issues. I know it did for me, and per PAC Tech, you do not want the resistors touching.

 

Ive always twisted a pair of resistors and have never had any issues.