I recently purchased a 1985 Bronco II with a stereo that didn't work very well, so I am putting in a new one. But the wiring seems very confusing, compared to other wiring I have seen. I need to know what the schematic is for this model and the color coding for the wiring.

 

THROW ALL THE OLD WIRES AWAY EXCEPT THE BATT POWER, AND THE ACC POWER RUN NEW SPEAKER WIRE IN THE DASH AND UNDER THE DOOR KICK PANNELS TO THE BACK. YOU CAN GROUND THE STEREO ALMOST ANYWHERE IN THE DASH. IF EQUIPED YOU CAN TAP IN TO THE LIGHT IN THE CLIMATE CONTROL PANEL FOR ILLUMINATION DIMMING. FOR EASIER INSTALL AND PROPER CHANNELS LABEL THE WIRES AS YOU RUN THEM. ALL THIS IS ASSUMING THAT THE STOCK WIRING HARNESS IS NOT PRESENT AS WAS THE CASE IN MY B2. IF IT IS GO TO WAL-MART AND GET THE ADAPTER FOR 4.00$

 

If you're planning to install a stereo requiring seperate grounds (-) for each speaker, usually found in the higher-than-standard power output (25W/ch or so) units, you'll not be able to use the factory speaker wiring configuration as it's set up at the radio interface.

The factory wiring ties the ground(-) wires together in the harness about a foot away from the right-front roof pillar. If you've got some sort of continuity tester (DVMM or battery powered test lamp) and the patience to pull the dash covers off (rather involved, though not much more than pulling carpet threasholds and running new wires to the rear), you can unwrap the harness starting at the radio connector, until you get to the crimp-splice. There cut the splice, but save the one black(with other colored stripe) wire to connect to one of the speaker's black wires.

Using the continuity checker, determine which positive(+) speaker wire corresponds to each ground(-) wire. You'll be sending a small current through one of the speakers and may hear a soft popping sound as you touch the wires with the tester. Flag the pair with a notation as to which speaker they go to.

Add three more, about 3-foot long black wires (soldering is ideal - crimp-splicing is satisfactory) to the remaining speaker ground(-) wires to reach the new radio, testing for continuity and marking accordingly like the first one as described.

Once all four speaker ground wires are in place, carefully re-wrap the harness with the vinyl (black) electrical tape up to about where you want to hook up the new radio. It's a good idea to double-check your speaker wires' continuity and check for cross-shorting before going the rest of the way toward hooking up the new stereo.

This is how I did my '84 B-2, replacing the factory AM-FM-Cassette with a Kenwood AM-FM-CD receiver. I also happen to be an electronics technician with over 20 years experience in audio, video an computers so what I just described might be a little more than some could handle.

Know your limitations and give yourself a day or two to tackle this just in case you're not too sure of your ability. Take your time, don't get in a hurry and everything will go smoothly and you'll have done a job to be proud of!

Any job worth doing is worth doing right.