88 Chevy Electrical problem

[NewTruckDriver]

I am new to this forum, so I apologize if this has been answered before.

I have a problem with a 1988 Chevy 1500 4x4 with a 5.7 V8, 3 speed automatic transmission with overdrive and aftermarket Fisher plow. The problem is as follows:

The directional signals for the truck and plow frame do not work, and the backup lights are out. I checked the backup/turn signal fuse, and even replaced it with a new fuse. There was no change in the symptoms. There was also an in-line 20 amp glass fuse that appears to be part of the plow light system that was burned out, and I replaced it. I checked the truck out after that, but there was no difference in the symptoms.

Also, with the plow switch in plow mode, the high and low beam headlights work. In truck mode, the low beams work, but the high beams don't.

I haven't gotten a chance to check the fuse panel and wires with a voltmeter, but I have to get this truck ready for a long trip in a hurry. I hope someone more knowledgeable than me in this area can respond with an answer.

[starfiresx]

NewTruckDriver, Welcome to the wonderful world of plow trucks.

are your turn lights working in the back? not the front?

it is amazing the amount of rust my 94 has at 168,000 miles compared to my 91 that has over 222,000 miles.

I my self have a 94 1500 with a plow. and let me tell you. the front lights on mine where in need of some work when I bought my truck two years ago.

for the park/turn lights. it is most likely a bad ground of just bad wires. as they are in a bad place. being out in all the bad weather. see as most places that put the plow on do a bad job of wiring these in the first place. they most of the time just use a pinch connecter. and this leads to bad corded wires. it took me a good day to get mine to work.

for your head lights. the wires run from the main harness. they tap into it for the plow lights. then the wire runs back into the cab. then thru the switch. to select where the power goes. you will just have to trace the flow of power and see where it stops.

it is not going to be a fun job. but do your self a favor. fix it right the fist time. use a soldering iron and shrink wrap all the wires. and cover them with wire loom. strap them out of harms way. you will thank yourself later.

for your back up lights you may have burnt bulbs or think about this one. it being a plow truck like mine, the column shifter is probably worn out. mine is very lose. I can get my back up lights to come one with out my truck being in reverse. could be a bad switch or again the elements have taken there toll on the wiring.

just trying to help. but I may not be much of that.

Joe