'86 C4 Bose Radio/Speaker Problems
Instructor
Joined: Mar 2010
Posts: 216
Likes: 4
From: Shrub Oak NY
Also on a lot of relays used inside the skin of the car and not sealed you can coax the plastic cover off and see the coil and contacts inside. Sometimes that helps, you can see burned contacts and what is on each terminal.
Race Director
Joined: Dec 2006
Posts: 10,383
Likes: 4
Here is a schematic of suspect relay...How do I bench test??? http://forums.corvetteforum.com/phot...?ppuser=386563
To identify the pins look at the color of the wires in the factory loom.
The wires should be dark green, black, and two orange.
When the radio is on, the head unit sends 12v through the dark green wire which passes through the coil and grounds in the black wire. One orange wire is powered on when the key is turned to run/accessories. It will pass through the closed relay and power the speakers and send the antenna up.
So, figure out which pin contacts the dark green wire. Put +12v DC there. Figure out which pin contacts the black wire. Ground it to your power source's ground. ("-" side of a battery for example)
Put your multi-meter's probes on the other two pins and test for zero resistance.
Disconnect the power supply and test for infinite resistance.
