barrypaul2005

I have a 1989 corvette that had the Bose system replaced and an aftermarket radio installed years ago – it was a pioneer that did have the ‘power antenna’ or ‘remote’ wire and everything worked fine – I didn’t do the work but had it professionally installed – they at least had everything hooked up correctly – you can see the spaghetti mess with the radio out.

I just installed a new aftermarket radio Blaupunkt since my CD player went on my old unit – and wanted to upgrade for the Bluetooth and sd card inputs.

You can see the 8 wire speaker connector and the 3 wire power connector that plugs into the new unit hanging on the rightside. The power antenna wire is the pink to blue/white wire dangling above the center not yet connected – the new radio unit didn’t have a wire for this (the pioneer unit I replaced did though).

I believe all the cut wires dangling on the left side were original from the BOSE unit that isn’t needed anymore.

Here’s my problem: The new radio unit is operational when I connect up the harnesses but when the key is in the ‘accessory’ position, the radio does turn on but nothing else comes on – my dash is blank. When ignition key is turned ‘on’ all seems well. What would cause the accessories position to now fail except for the radio?

Also, I assume I just need to hook up the power antenna wire (pink to blue/white wire) to the acc wire so that whenever the car is on the power antenna would be activated – but I can’t get the power antenna to raise up on the acc 12 v line (confirmed 12 v is present when measured using ground from battery) but it does raise when I connect to the battery 12V to this wire. Fuses are OK – the 2 problems may be related.

... and just confirmed that even though +12v is present on the 'acc' line when the key is in that position - it's only 12v when there is no load. When I connect the power antenna lines - the antenna doesn't raise and the voltage goes to zero - so I think I'm getting closer. Appears that the 'acc' line is simply not behaving correctly - I'll have to trace back that line - should just go back to the key ignition switch (right?)

Anyone with some knowledge of this spaghetti mess behind the radio that could lead me to a solution, so frustrating when all was working fine before I rewired ? Is there an ACC fuse or relay somewhere - I don't see anything in the fuse box?

barrypaul2005

... the more I think about this, I'm guessing that I simply lost power to the 'ACC' lines (with the key in that position). So is there a fusible link dedicate to that line somewhere that I can check?

GREGGPENN

I think they may be related too. I would not assume you can drive a power antenna off the accessory circuit. It's normally designed as a "memory" lead -- meaning low current. OTOH, I don't know (w/o looking at my manual) if the power antenna uses an "outboard" relay? If not, it seems likely you are pulling too much power on the accessory lead....causing the drop to zero in current AND possibly blowing a fuse that you don't see. I'd also confirm you aren't reversing POWER/ACC leads.

I also don't remember if there is a relay associated with the Bose system in general (possibly to trigger/drive the speaker amps) and if you (or the po) dealt with that correctly? My gut says to ignore this thought...but why not post it just in case? OTOH, if there IS a relay, maybe you could use that for the power antenna circuit. Doesn't the Blaupunkt have an antenna trigger? It SHOULD if it has a radio.

I don't think you have a problem with a fuseable link because anything that feeds the dash would blow a fuse before a fuseable link. I'm not even sure FLs are used to power equipment outside the engine bay.

barrypaul2005

Thanks Greg, your comments are helpful. Since all is well when the key is 'on' - then as you say fuses and fusible links would be OK - there's no separate ones for key 'on' vs key 'acc' positions.

The Blaupunkt unit (Detroit DTR100BT) has no other leads beside the 3 power and 8 speaker wires. But I am sure that there is a relay in the vette that is powering the antenna motor - so when I fix the current problem I should be able to use the 'ACC' wire to power up the antenna. Only difference is that the antenna will go up when the car is on as opposed to when the radio is on. If this turns out to be a problem I'll have to add a switch (via a fused wire) to the main power. The previous Pioneer unit did have a 'remote' wire coming out that had +12v when the radio was turned on.

... after thinking more, I'm sure the problem is the ignition switch, or the mechanical linkage from key to ignition switch. I'll get under there and investigate and start from there.

I didn't assume this before because I didn't touch that area when installing the radio - but now I'm thinking it may have been like this before for a little while - I rarely have the key in the 'ACC' position and vaguely recall a hiccup before thinking it had something to do with the steering column not being locked. Really could be the mechanical key linkage to the ignition switch - since I replaced the ignition switch about 3 years ago (so did mess under there before).

It's funny as you can see in the picture all those dangling wires - that may be just a red herring and added my frustration. I had the battery disconnected when I spliced the wires - and also noted that the 'ACC' line there going to the radio does have a in-line fuse, so I would have protected the circuit either way.

I'll post the results of the investigation shortly.

barrypaul2005

Problem Solved

I got out the wiring diagrams and found the 'ACC' line right off the ignition switch. Took the seat out - got underneath and tapped into the wire (it's the brown wire in the blue harness on the ignition switch input/outputs).

Measured +12V when key switched to 'ACC'. Then checked continuity to 'ACC' radio wire and measured 1 ohm. Turns out the original fuse I left in from the pioneer unit uses a fuse-resistor. Then I tried to raise the power antenna at the end of that wire (as before)- no luck. Turns out that fuse drops the voltage significantly. So I then tried to raise power antenna tapped into before that fuse - and sure enough, antenna raised. Simply just needed to get rid of that resistor fuse. You can see that resistor fuse (from my previous Pioneer Radio unit) in the red wire clearly at the bottom.

Silly me - that was the only problem, I didn't realize that the 'ACC' position leaves all the dashboard lights off (that's why I thought I lost the accessory lines' voltages).

Glad I didn't have to drop the steering column to get at the ignition switch. Lots of time diagnosing this silly problem - at least I got to vacuum clean under the driver's side seat.

No wonder I couldn't find any one that lost only 'accessories' in that key position. Nice to have the simple screw on the battery terminal to disconnect the battery.

I'll sleep a lot better tonight.

whalepirot

Hoping those twist connectors are not permanent.

ghlkal

Great, and thanks for posting the solution.

barrypaul2005

I decided to install a simple toggle switch to control the power antenna instead of it coming on every time the car is on. Just connected between the power antenna blue wire to the 'ACC' wire. I didn't want to connect to 'Battery' wire in the case that I forgot to turn it off when I exit the car - I think power would always be going to the power antenna relay in that case.

Makes sense - the funny thing is the reception on FM is just as good in my locale, crystal clear, even with the antenna down. Nice to save wear and tear on that power antenna - maybe even a saving a little juice when in 'ACC' position too.

Yeah... I know I shouldn't use those threaded screw connectors - originally used to ensure everything is initially OK. But I decided to keep them since they very secure and sure will make replacing the stereo in the future that much easier. I taped them up to make sure that they are not dangling.

barrypaul2005

Confirmed - no blue wire - just the 3 power wires and 8 speakers wires- I tried to upload the manual but it's slightly too big a file. It's Blaupunks model DETROIT 100 BT.

I'm actually happy it doesn't have that wire - I really like independent control of the power antenna.

xrav22

I just put a new stereo
( )
and used the blue wire for power ant. The old stereos used to have blue(amp) and blue/white(antennae) but now it is just blue for both I guess.
It was a discount stereo to not have that wire.