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George H.
George H., ASE Certified Technician
Category: Chevy
Satisfied Customers: 18565
Experience:  GM Tech ASE Master Tech 15+ years
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I'm working on a 1998 C1500 4.3 automatic. I 't have power

Customer Question

I'm working on a 1998 C1500 4.3 automatic. I don't have power to the starter from the purple wire. When I check the N/S I have power on a red wire with the ing on and power out of the purple wire when ing is engaged in start mode. All other power functions seem to work fine.
JA: Sometimes things that you think will be really complicated end up being easy to fix with a Chevy. The Chevy Mechanic I'm going to connect you with knows all the tricks and shortcuts. Are you hoping to fix this yourself?
Customer: yes.
JA: Great! What have you tried so far?
Customer: All the fuses have power to both sides, changed relays a couple of times, rechecked ground wires, traced power coming from the N/S.
JA: Is there anything else the Chevy Mechanic should be aware of about your Chevy?
Customer: not at this time
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Chevy Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: Chevy
Expert:  George H. replied 1 year ago.

Hello I will help you with your question,

You say you DO show 12 volts out on the purple wire at the safety switch with the key in the start position?

Customer: replied 1 year ago.
No volt meter just a test light, yes
Expert:  George H. replied 1 year ago.

OK, next stop is the start relay in the underhood fuse block. You should show power to two of the pin sockets with the key in the start position, if you do connect a paperclip between the #30 and #87 pin sockets and see if the starter cranks the engine.

Do you know how to check ground with your testlight?

Customer: replied 1 year ago.
It will be later today before I can work on it. To test a ground you just do the opposite of checking for power, correct?
Expert:  George H. replied 1 year ago.

That is fine I will be here all day.

Yes, you place the clip of the test light on a positive voltage source and touch the tip to the #85 pin in the relay socket. If the light comes on you have ground.

Let me know what you find

Thanks

Customer: replied 1 year ago.
Will do.
To give you more history on this truck. I bought it with a blown motor( rod thru the oil pan) to put a 4.3 with a fresh 4l60 from another c1500. Both have the same engine codes, transmissions mfg date with in a month. Other than the paint they are a mirror image.
It does gave a Clifford 1.2x auto start and door lock on it. I talked to the local Clifford dealer, he assured me that this model would not affect any functions when using the key.
The person I bought it from had no clue it was on there, so I don't have the remotes.
Expert:  George H. replied 1 year ago.

I would remove the clifford system after you check the relay and we determine what is missing. They would HAVE to tap into the starting circuit for the remote start so the dealer is not telling you the truth and most of the time those systems turn in to junk after a few years due to the harsh enviorment.

Check the relay that will let me know which direction we need to go with this

I will watch for your post

Thanks

Customer: replied 1 year ago.
Had the starters tested and have not put one of the on yet but this is how it tested,
Pin 86 good ground key on or off
Pin 30 hot key on or off
Pin 85 & 87 no ground or fire
Expert:  George H. replied 1 year ago.

So only one of the pins shows 12 volts with your light?

The purple white wire at the neutral switch that you measured 12 volts at before when you turn the key to the start position feeds the #85 or #86 pin of the relay.

Double check your readings, if you have 12 volts at the switch with the key in start but not to either the 85 or 86 then you need to find the break between the two.

You can test the starter on the vehicle with the paper clip as I posted above.

Let me know what you are seeing

Thanks

Customer: replied 1 year ago.
Purple has power out when starter engaged. Purple with white as nothing. The hot wire going to the switch is a pale red or pink. Yellow wire has nothing.
Expert:  George H. replied 1 year ago.

I don't understand, the purple wire runs from the relay to the starter, you can energize that with 12 volts by using a paperclip from the #30 to the #87 and the starter should run to turn the enigne. IF it does the starter and that half of the circuit is good.

The purple white wire at the neutral switch should show 12 volts when you turn the key to the start position AND the #85 or #86 pin at the relay socket should show 12 volts from that same purple white wire when the key is in the start position.

At this point this is the only wires and testing we are concerned with.

Let me know what you measure at those points

Thanks

Customer: replied 1 year ago.
Got dark and cold so I'll have to try again tomorrow evening.
Customer: replied 1 year ago.
I did jump it and it will crank. So at least I know that.
Expert:  George H. replied 1 year ago.

Ok, just concentrate on the pins of the starter relay, in the start position you should have two pins that show 12 volts, if you do not go back and check the purple white wire at the switch.

let me know what you find

Thanks

Customer: replied 1 year ago.
I've also wondered if I've skipped a ground wire some where.
Ryan side, body to frame, motor to frame.
Rt front. Battery to motor and one from the harness.
Harness to thermostat housing.
Expert:  George H. replied 1 year ago.

The ground should be present at the relay, that is what you are checking after you determine that you have two pins with power, if you have the cable from the battery bolted to the block next to the starter then you have ground. We can get to checking for poor connections after you confirm you have power to the starter on the purple wire when you turn the key.

One step at a time.

I will be here tomorrow so let me know how I can help

Thanks