Power issue with VDO TR7412UB in my 01 Z3

[sdmike1]

Hi folks -
I just replaced my stock CD43 Business CD with the VDO Continental TR7412UB and everything works great except for one thing - switched power. I have confirmed with a volt meter that I have always-on power at pin A7 and switched power at pin A4 per the manual, but my HU will not power off when the key is turned off. I'm assuming that's what pin A4 does. I checked it all the way down to the pins at the back of the radio and confirmed the 12v power cuts off, yet the radio stays on. I know this is a popular upgrade HU for E36's, so hoping someone has encountered and solved this. For fun I put the switched power on A7 and the unit turned off just fine with the key. However, it also lost the time and other settings. The seller (Race German) says he's sold hundreds of these and that's the first time he's seen this. Help?

Continental_pinout14853083121497841710.jpg145334456_10221857250677956_729110768828520716_n.jpg145644386_10221857251517977_4836957523712741869_n.jpg146116463_10221857250837960_2967010226676559117_n.jpg

[DennisCooper]

Hi,

You've done the base level fault finding, pin A4 is switched and when you turn the key, there's no power to that pin. Connect pin A7 to the constant 12V supply of the head unit and A4 (switched power) to the switched power input of the head unit.

Make sure you have a good ground/earth and connect the speakers up, and re-test. If the unit still doesn't now switch off with the key turn, then seems likely you have a faulty unit. If it works properly, then all good. Vaguely, I recall some head units would only behave properly when everything was connected - just remembered, connect the antenna as well !

Cheers, Dennis!

[sdmike1]

Thanks Dennis. What you see in the pictures is everything hooked up, although you can't see the antenna. The hot wire is on A7 (shown at 12.2v), and the switched/ignition wire is on A4 (shown at 0v with the key off). Funny, when that picture was taken with 0v at pin A4 the unit was on and playing. So seems that the unit has a short to power inside.

[sdmike1]

Oh for cripes sake

While I was investigating some settings (which have terrible documentation in the manual) thinking I might find something, I turned off the key and the unit turned off. WTF? Testing various scenarios I learned that it will shut down, but it will also work with the key off, which requires manual shut-off. So I don’t know if it fixed itself or if during all the fiddling with it or I had always turned it on manually with the key off which required manual shut-down. Well, that was 36 hours of unnecessary messing around. Lol

[MarcoZandrini]

Yeah, but you’ve sharpened your troubleshooting skills.

[sdmike1]

Yeah, but you’ve sharpened your troubleshooting skills.

lol. Yep. Silver lining