01 Blazer wont start

[61_FL_Apache]

I bought this truck a few weeks ago and starting having this issue where it would not start form time to time.

Here is a video of what is happening.

http://youtu.be/pK8WCL4Am4M

The battery, starter, neutral safety switch and starer relay appear to be fine. I suspect the ignition switch it self, but I dont have another one to try.

What do you guys think?

[61_FL_Apache]

Is it possibly this part?

http://www.ebay.com/itm/Ignition-Sta...7e7aee&vxp=mtr

[68C15]

the ignition switch usually fails on IGN3 circuit, not START circuit.

check for no crank signal at manual lever sensor (neutral safety switch) on yellow wire. if you have power there during cranking the switch is fine.

I'm at home now and don't have access to diagrams but if the steering column goes in the customer's 57 Bel Air nicely tomorrow morning I'll look into this for you.

[61_FL_Apache]

Thanks!!

[68C15]

Brought my iPad home.
Yellow wire from pin D1 on ignition switch feeds to "crank" fuse under hood. Then purple wire to neutral switch. Then purple-white wire to start relay under hood. Relay control side grounds at G102 (right rear of cylinder head).

If you remove relay and jumper the top right to bottom left cavities in fuse box it should crank over. Try that and report back

[61_FL_Apache]

Originally Posted by 68C15

Brought my iPad home.
Yellow wire from pin D1 on ignition switch feeds to "crank" fuse under hood. Then purple wire to neutral switch. Then purple-white wire to start relay under hood. Relay control side grounds at G102 (right rear of cylinder head).

If you remove relay and jumper the top right to bottom left cavities in fuse box it should crank over. Try that and report back

Is this to eliminate the starter relay? If so, I did swap it with one from the defroster which this truck does not have. There was no change.

[95 S_Trucker]

That will check the starter circuit and the starter itself.



There are 2 circuits involved. The load circuit and the control circuit.

The load circuit will start at the battery, go to the relay, then go to the solenoid.

The control circuit will start at the battery, go through the ignition switch, go through the neutral safety switch, and end at the relay(eventually ground).

68C15 Is directing you to insert the jumper and see if it cranks. If it does, the load circuit is operating just fine.

I will snap a pic of the diagram and post it.

[95 S_Trucker]

Draw a line right down the center of the relay. By jumping the relay terminals in the fuse/relay box, you are verifying everything on the right side of the line.

[68C15]

does it crank with relay jumpered?

[61_FL_Apache]

Ok. Being this is an intermittent problem, I was able to start the it when I went out there.

I removed the relay, then jumpered the top right with bottom left of the starter relay and the starter kicked the engine over. When I put the relay back in, it did not start.

[95 S_Trucker]

Did it start with the key? Or did it start when you jumped the relay?

Remember that imaginary line you drew through the relay? Your problem is on the left side of the line. It could be the ignition switch, neutral safety switch, or wiring problem.

[61_FL_Apache]

Originally Posted by 95 S_Trucker

Did it start with the key? Or did it start when you jumped the relay?

Remember that imaginary line you drew through the relay? Your problem is on the left side of the line. It could be the ignition switch, neutral safety switch, or wiring problem.

It did start with the key the first time, but just turned over with the jumper.

[61_FL_Apache]

When I did the test above with the jumper, I did not have the ignition key in the Run position. I can redo that test later today.

[68C15]

Originally Posted by 61_FL_Apache

When I did the test above with the jumper, I did not have the ignition key in the Run position. I can redo that test later today.

Don't need to. Your problem is it's not cranking.

Check top left and bottom right of relay socket for ground with key turned off.

one end of test light on positive battery post and probe the sockets GENTLY so as not tot damage connectors. The light will illuminate when you probe a good ground

The other (either top right or bottom left depending on which is ground) should have power when you try and crank it with key. This time have test light hooked between negative post and other socket under starter relay

[68C15]

^^

This test does 2 things. To see if control side of relay has good ground and also to see if circuit ahead of relay is good on control side

[61_FL_Apache]

Originally Posted by 68C15

^^

This test does 2 things. To see if control side of relay has good ground and also to see if circuit ahead of relay is good on control side

Ok. Then that test passed. It did crank when tested.

[61_FL_Apache]

Im planning on replacing the starter switch this week. It seems to be the most likely part to fail. I will report back after I replace it.

[61_FL_Apache]

I replaced the starter switch today and that took care of this issue. Thanks to you guys for the help with this!