How to Troubleshoot a 1988 Chevy Cheyenne Truck
I am doing an article on troubleshooting a chevrolet Tahoe electrical system.
- Difficulty:
- Moderate
Instructions
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First thing is to isolate where the problem is and what other items aren't working either, sometimes there are two or three things on the same circuit. Look for any burnt wires, or charred switches. If it involves the rear lights and they are all messed up then the most likely thing to look for is a bad ground to the chassis, and lamp grounding.
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If the above checks out then you have to find the fuse box, that usually is under the drivers side dashboard. Now look for the fuse identification chart which gives the fuse size and amperage of the fuse. When you find the fuse, pull it out and check it with an ohm meter, set on resistance, it should show zero or it will buzz. If the fuse is good then take the volt meter set to 12vdc and touch across the two fuse prongs and check polarity red to positive and the black to negative or ground. You should read a 12 volts or less, and if no voltage, then try turning the key to Acc or on, and check again. And if you still get no voltage, then you have to check the ignition switch, you will have to get to the wire harness in the back and check all the prongs marked with acc. or on. or + pink or red or red stripped wires, and put the meter in volts and put the black probe on a metal chassis ground, and the red positive probe on the wires and check for 12 volts.
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If you don't get any voltage at these points, then you will have to look under the hood for an inline fuses and check them for voltage. If no voltage is found, then go further on to the battery terminals, and strip a little back of the wire to get contact for the red probe. Check all the small wires on the positive battery post, all should have 12 volts, if not hen you have a bad battery connector and has to be replaced. Next if you get power to the fuses and the fuses are good then the next step is checking any switches that control the item. If you have more then one item not working then it will not be a switch but probably a relay, these are small as 1x1 inch or as big as 3x3 inch black plastic boxes that plug in. They will be under a large black plastic box that snaps closed. Unsnap the cover or take the cover screw out and look for the relay that is marked as the item that does not work. Take the relay to AutoZone or similar auto parts shop and they will check it for you. In any case the grounds should all be checked by using a jumper wire with alligator clips on each end to clip to the ground on the item and the the other to a grounded area on the car. (bare metal)
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Tips & Warnings
Any type of continuity tester will work for checking switches and fuses.
Any 12 volt dc tester will do for other tests like to check for 12 volts.
never connect a jumper wire to any 12 volt supply wire or red colored wires or you could cause a full short in your vehicle and start a fire.
Never check anything on the fuel gauge or sending unit in the tank unless you disconnect the battery positive terminal on the battery. You could cause an explosion in your fuel tank, Veeeeeery Dangerous!
