[SwedishChef]

I pulled the factory head unit out of my '95 Classic LWB and meticulously rewired each harness wire to the new stereo loom, and now I'm just getting a hiss through all the speakers! New head unit (Parrot RKi8400) powers up and connects to my iPhone and appears to play music, but no music comes through the speakers, just the hiss. I've attached all grounds but not the antenna (need adapter). Any ideas?

 

[SwedishChef]

So apparently there's a known issue with swapping head units in my car that produces this hissing noise. Does anyone know how to address it? Something to do with too much power from the new head unit?

 

[SwedishChef]

So I've read up on a couple ICE forums and it sounds like the possible issue is the factory amp - the new HU is creating far more power than the factory HU, and the amp is, well, amplifying it. I'm going to look at bypassing the amp.

 

[texasdiver72]

When I installed my aftermarket stereo, I wanted to maintain the original wiring as closely as possible so that I can go back to original if I want to. I went around all of the existing wiring and wired the speakers directly to the new head unit. I pulled the subwoofer box and amp out of the back (stored it) and put a 6.5" bazooka tube with integrated amp. Installed that using the existing 12v power in the rear of the truck.

Sounds great and took no time at all. Running the wiring in these trucks is simple because everything is wide open.

 

[Paul Grant]

The factory head unit put out no power at all. The HK amp in the was responsible for all the power in your '95. It was a multi channel amp that drove all the speakers. All that came out of the head unit was the signal. That's were your problem is. You're running a powered head unit into another amplifier. I'm surprised ALL you're getting is a hiss.

 

[SwedishChef]

When I installed my aftermarket stereo, I wanted to maintain the original wiring as closely as possible so that I can go back to original if I want to. I went around all of the existing wiring and wired the speakers directly to the new head unit. I pulled the subwoofer box and amp out of the back (stored it) and put a 6.5" bazooka tube with integrated amp. Installed that using the existing 12v power in the rear of the truck.

Sounds great and took no time at all. Running the wiring in these trucks is simple because everything is wide open.

Is the subwoofer box that huge black plastic thing the amp is bolted to? Looks like some sort of industrial fluid container.

Also, since I'm getting no music, just hissing, do you happen to have the wiring diagram you used for the stock HU?

 

[SwedishChef]

The factory head unit put out no power at all. The HK amp in the was responsible for all the power in your '95. It was a multi channel amp that drove all the speakers. All that came out of the head unit was the signal. That's were your problem is. You're running a powered head unit into another amplifier. I'm surprised ALL you're getting is a hiss.

Very useful info. Thank you. I'm surprised too - it leads me to believe I may have used the wrong wiring diagram for my HU swap.

 

[76FJ55]

If you get a copy of RAVE it has the stock radio wiring diagrams in it.

 

[SwedishChef]

If you get a copy of RAVE it has the stock radio wiring diagrams in it.

That's actually the one I used. My concern was the differences I was stumbling upon from the pre-95 classic and the P38. Seems like the '95 Classic model year is a bit of a ghost for documentation.

 

[76FJ55]

In rave choose RR Classic; then go to the bottom to Electrical Troubleshooting Manual - 1995 -Export - 2nd Edition. This should fine you all the electrical diagrams for the 95 RRC.

 

[SwedishChef]

In rave choose RR Classic; then go to the bottom to Electrical Troubleshooting Manual - 1995 -Export - 2nd Edition. This should fine you all the electrical diagrams for the 95 RRC.

Wow great tip. Thanks.

 

[SwedishChef]

Ok — took it to my local audio shop and they figured it out. It was to do with the amp. The wrong signal strength (or something) was coming to the speakers because of the amp. I had manually spliced the new HU harness into the factory harness using the factory wiring diagrams, which was all done correctly, but I needed to use the RCA cables instead of the loom for the speakers because of some different signal strength. It's still not quite right, but it works.