Volkswagen Passat Forum banner
1 - 10 of 10 Posts

·
Registered
Joined
·
6,874 Posts
Discussion Starter · #1 ·
Ok... first off... this isn't for a B5/B5.5... so it may be testing your knowledge of "older" european vehicles.

The subject: 1987 Volvo 760 Turbo Intercooler (yes, its really called that)

The challenge: Installing an aftermarket HU.


So I'm helping my cousin by installing a HU in his first car ever, an old hand-me-down Volvo. I got the proper wiring harness, and wiring diagram. After ripping out all the old stuff, including the factory amp, I soon realized that Volvo's are wired wierd. The harness was all wrong; the diagram didn't match; and worse of all, none of the wires were consistently colored. It was a big fat mess. Fortunately, the yellow wire, the balck wire & the red wire were all still consistent (battery, ground, switched power). However, the rest was a challenge.
After a little bit of common sense, educated guessing, and experimenting, I isolated & identified all of the speaker wires.
So I kiboshed the harness & just wired it in directly.
Speakers - done
Ground - done
illumination (orange) - done
battery/constant - done
switched power - done

But now I'm left with these two wires that were joined together at one plug on the harness. I couldnt firgure out what they were for. They were both green with a red stripe. After some experimenting, I realized they were somehow connected with the interior lights (specifically, the dash lights). I didnt know how they were integrated into the HU so I left them alone. When I finished wiring everything, the radio would not power up. I was at a loss. I then remembered the two wires. I put them to the
constant, but then the interior was lit up all the time, so I knew that wasnt right. So I tapped it into the switched. When I did this, I discovered that the radio turned on! So heres the dilemna. When the radio is wired by itself to the switched power, nothing turnes on. When I wire in those two wires, the radio will only power on when the light switch is turned on too. so basically, the way it is now, I can only listen to the radio of the lightswitch (dash & headlights) are switched on.

Help.
 

·
Registered
Joined
·
1,172 Posts
That wire sounds like the illumination to me. I'm surprised there wasn't a factory amp in that car, that's lucky. Not to sound condescending (can't spell the word) but are you 100% sure that you tested your switched, constant, and ground wires? It doesn't sound like you have a switched wire to me. Let me think about this some more.

-Mike
 

·
Registered
Joined
·
23,182 Posts
I agree with Mike. Grap your multimeter and test the power, acc., and ground leads. I have a feeling one of them isn't wired correctly. IIRC the dimmer lead in the Volvo is wired to the battery so I'd look at the power and acc. leads. Does the HU lose memory when you turn the car off? If not I'll bet you have the acc. lead wired incorrectly. If you are losing memory then check the battery lead first.


Paul :thumbup:
 

·
Registered
Joined
·
6,874 Posts
Discussion Starter · #4 ·
Thanks! But I dont have a multimeter.

And btw, the car DID have an amp. I ripped that sucker out.

Im guessing my switched power wire is a dud (the red). I will see about tapping in somewhere else. Perhaps the lighter? Suggestions?
 

·
Registered
Joined
·
23,182 Posts
Joe, before doing anything else, I'd hit up Sears. They have a number of great MMs for $20-$25. Like anything else it's best to know something than to guess, especially when dealing with electricity.


Paul :thumbup:
 

·
Registered
Joined
·
1,172 Posts
Even if you don't want to spend that much just go out and buy a cheap "computer killer" test light. Very easy to use and effective if used properly. These aren't always the reccommended tools of the mobile installer but used carefully and wisely, test lights are very efficient. Probably cost you $5-20 depending on where ya go.
 

·
Registered
Joined
·
6,874 Posts
Discussion Starter · #8 ·
Mike/Paul,
Just wanted to give you guys a quick update. I followed your advice & got a test light. Boy, am I glad I did. Made the job a LOT easier. When all was said & done, I was delighted to see my guesstimations for the speakers were dead on (they were all sorts of wierd colors).
The issue I was facing was getting the radio to power on without having to switch on the headlights. At first I thought my problem was the switched power. After using the tester, I was surprised to see my switched wire was fine. It was the constant. For somereason, it was wired to the headlight switch. There was no other constant line for power... wierd huh? I finally decided I wasnt going to spend any more time looking for a constant on an 18 year old car. I just drilled throught the firewall & routed a direct tap to the battery. Problem soved!

Two last questions:
1) The car has a factory power antenna. I didnt see a wire on the aftermarket to power it up. Can I tap into the remote (blue/white wire on the Pioneer) to turn it on? I have the remote hooked up to an amp (for the minisub in the back)... can I just splice into that?

2) I'm at a loss with waht to do with the illumination wire (orange & white on the Pioneer). I guess I can just leave it unwired... but the HU will never dim at night. Do you think I should wire it to that wire I thought was the constant?

THANKS AGAIN FOR ALL YOUR HELP GUYS!!!!!!!!!!!!!!!!!!!!!!
 

·
Registered
Joined
·
290 Posts
Did you find the amp up in the driver's side knee bolster to the left of the steering column? I used to have a 1988 740 Turbo. If I remember correctly, there was a switch on the dash to control the power antenna position, and one of the leads does go to the center console, so you should be able to use the accessory power wire that you're using for your new amp.

Also, if you do end up picking up a multimeter, you can use it to see if the voltage on those questionable dash light wires changes when adjusting the dash light rheostat. That should make it easier to figure out the dimmer option.
 

·
Registered
Joined
·
23,182 Posts
BoeserBlick said:
Two last questions:
1) The car has a factory power antenna. I didnt see a wire on the aftermarket to power it up. Can I tap into the remote (blue/white wire on the Pioneer) to turn it on? I have the remote hooked up to an amp (for the minisub in the back)... can I just splice into that?
Yes, that'll work fine Joe. Pioneer doesn't use a separate lead for the power antenna and amp tunr on leads. :crazy:

2) I'm at a loss with waht to do with the illumination wire (orange & white on the Pioneer). I guess I can just leave it unwired... but the HU will never dim at night. Do you think I should wire it to that wire I thought was the constant?
Leaving it unhooked is fine. If he wants to dim the display he can do it manually or you can wire it to a 12V source with a switch and then he can use the switch to activate the dimmer. Last resort is to find the 12V lead at the HL switch and wire into that.


Paul :thumbup:

THANKS AGAIN FOR ALL YOUR HELP GUYS!!!!!!!!!!!!!!!!!!!!!![/quote]
 
1 - 10 of 10 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top