1990 Chevy 1/2 ton 4/4 truck with auto and 350v8. wiper problems
1990 Chevy 1/2 ton 4/4 truck with auto and 350v8. I recently burnt the wiring harness up because of a back fire. Have replaced the harness with one out of a 1989 truck 4/4 380v8 same as mine. All plugs matched up ok except my harness had a gray plug wire by the computer harness, the 89 did not have. Also the oil sending unit on the engine has two prong plug as the 90 had a three prong plug, I took the sending oil unit off the 89, so it plugs in. My question is this my wipers don't work right and the washer does not work, the harness for the wiper motor pluged in was the same 4 wires plus a middle black wire. When i turn on the wipers the oil guage and check guage pulsate back and forth, only works on high speed no low speed and no itermittent mode, and the wiper motor buzzes when on delayed or low speed. I tryed to add a ground wire to the middle black wire on the plug, no good does not change, also the temp guage pulsates too. You folks have any ideas how to fix this before i have to try and take it to a shop?????? Your help would be greatly appreciated THANKS !
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Re: 1990 Chevy 1/2 ton 4/4 truck with auto and 350v8. ...
To whom it may concern, you cant used the harness of 1989 model to 1990 model chevy truck, even the sockets are the same a,b,c,d, thers a big different on wire distribution from the ecu. it better that you find harness on the same model, or if you still not yet finish that problem i will gave you the 1990 ecu diagram on live chat or contact me @ my ym
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Wiring diagrams for 1980 trucks are contained in a separate Wiring. Diagram Booklet.... Some of these service operations require the use of tools specially designed .... 1-1/2 Ton. 2-3/4 Ton. 3-1 Ton. 4-1/2 Ton (W/HDSusp). Fig. 0A-3-Vehicle Identification Number ... Right Hand Side of Cylinder Block at Rear of Distributor.
Still sounds off. Take the #1 spark plug out, put your finger in the hole and have someone bump the starter around. As soon as you feel pressure, or a whoof sound (air coming out the hole), stop cranking. Look at your timing scale on the crankshaft pulley: You should be very close to the zero scale on the pointer. Put a socket and wrench on the crank pulley if needed to turn the crank on around (clockwise) until the notch or line on the pulley is right with the zero mark on the pointer scale. Now you are at top dead center of the compression stroke on #1. Take off the distributor cap. The rotor should be pointing directly to the #1 spark plug wire tower. Now that you have #1, follow the firing order around in the direction the rotor turns to check if each of your plug wires are in the right place. Firing order should be stamped on the intake manifold. If a 350 engine, firing order is 1-8-4-3-6-5-7-2. You might need to check that, only going by memory from couple days ago when I had to do this. The cylinders on the driver's side are 1-3-5-7, front to back. On the passenger side, cylinders are 2-4-6-8, front to back.
Your best bet here is to go to the dealer or a reputable tune up shop and see if they will provide you with wiring diagrams for both years. If you explain your predicament, they will most likely give them to you.They don't like to tackle these kinds of jobs. Then you will have to go through them to see what is different.That is the only way to solve this problem.
Every year there are changes in the details with wiring harness and it's probable that you may have to change the position of some wires going into or out of the computer. Trace out the circuit on both diagrams and reconfigure the 89 harness to match the contact points and routing obf the 90 and you should be able to get your wipers working properly and your gauges to stop flashing. Hope this helps.
sounds like you still have a wire harness problem for the oil pressure sending unit. if you spliced a new pigtail to the wire harness you may still have a bad connection or there is still a damaged wire farther up in the harness.
The firing order is 1-8-4-3-6-5-7-2.
The distributor rotates in a clockwise direction. The engine must be on the compression stroke on the #1 cylinder. Line up the timing marks. Remove the cap and the rotor should be pointing to approximately the 5 o'clock position.