Fresh perspective please.

[edpdx]

I have been working on my starter problem for 2 months now. At first I believed it was the starter- pulled it found it was a 12V DD. Replaced it with a new 28MT gear reduction starter. Started right up. On the third startup all I hear is click. I put a new solenoid in because I know I shorted the 1st one to ground. Started fine the 1st, second and third time. The fourth one all I got was a click again. I ran the tests again and could not find anything out of whack. The batteries seemed a little weak, so I replaced them with group 31 batts. I just got finished reinstalling the starter and the new battery wiring and it starts right up until the 3rd try. CLICK!?!

Is there a circuit breaker or something I am not seeing in the starter schematic? Because I don't seem to be cooking the fuse in the block and I have not found a bad fusible link. It seems that after the 3rd or 4th time I wait for the "WAIT" light to go off something heats up enough to "trip".

Could this be the glow plug relay?

 

[Westech]

no there is no Starter fuse or Breaker. Have you replaced your stater relay under the dash and the one on the steering column ?

 

[doghead]

Is your under-dash starter relay original(stock)? Have you replaced it ever?

Have you removed all cables and cleaned them all?

Have you tested for voltage at the starter solenoid and motor, after the third try? Is there voltage there then?

 

[edpdx]

I replaced the original starter relay as per the Doghead mod. I just tested a few things:

The battery cable is getting 24v at the starter solenoid.
The Starter relay is getting 24v.
No power is coming from the "purple" post on the starter relay whether the key is in the ON or OFF position.

Just noticed that the purple wire attached to the relay is showing a ground?????????????????????

I'll remove it from the Starter Relay and test the wire lead without it being attached. <<<<<<<<<<<<<<<<<

Could this be a bad neutral replay/switch- the one at the bottom of the steering column?

 

[mistaken1]

Does the red wire have 24V?

The purple wire should only have 24V when the ignition switch is in the start position (assuming the relay is functioning).

 

[edpdx]

mistaken1, The red wire at the starter relay is giving 24-25 volts.

The purple wire is not getting any juice with the key in the ON position. It actually shows a ground.

 

[woodywood]

test it in the start position thats the only time the purple wire is hot!it can and will show ground similarities when not in the start position!

 

[edpdx]

More testing. Disconnected the purple wire from the relay:

1.Purple relay post does not get any power when key is ON.
2. Purple lead- disconnected, is showing a ground.

 

[edpdx]

Could it be the relay is bad? Its a new one from NAPA?...

But then again, it is ok for the first few starts. Could it be the BACK-UP LIGHT SWITCH?

 

[southdave]

I had somthing similar, the eight time it happen I went back greased all my connection on the starter and grounds. I also replaced the ground wires from the buss bar to engine and the engine to body. it working well for now....

 

[edpdx]

Southdave,

I checked the ground on this circuit. I even added an extra ground to the starter at the support bracket. It seems the relay is not working right because the purple post does not get energized when the key is turned. I think I'll go pull the steering wheel and have a look at this ignition cylinder and the wires... as soon as I get my flip flops on.

 

[southdave]

I can't remember, but is the relay grounded to the that plate it mounted to? Mine worked , after I replaced the engine to body ground strap at the fire wall replaced. it had kink in it. Then again maybe it was elfs... yet another reason to wear shoes..

 

[Warthog]

Remember that the NAPA relay is Made in China. It could very well be bad or flakey. For 1 few buck, it would be worth replacing. Other have posted the same part number for under $10 at other parts houses.

The purple wire will show a ground when disconnected. That is because the wire runs to the coil inside the starter solenoid, and that coil is grounded. When current flows it will follow the path to ground and energize the solenoid.

 

[rchalmers3]

Before you buy anything you could apply 24v to the purple wire (with the truck in park) and see if it cranks.

Rick

 

[edpdx]

rchalmers3, Yes it cranks if I jump the wire from the RED starter relay post to the PURPLE post. I just put a new Starter Relay in. I know:

The Starter Relay (SR) is getting 24V
The PURPLE post on the SR is not being energized when the key is turned.
The SR ground is sound as I have added a jumper to ground to be sure.
The Purple wire with White Stripe (P w/W) is the problem. *Somewhere in this circuit lies the issue. Looking at the wiring schematic I see a splice and some other things to check, I don't know where these are- labeled A, B, C & D. Can anyone identify where there are or any known issues I can check first. Please don't tell me to look at the TM. I have all of them open. I have reviewed the threads as well. The ones that sound promising have gone orphaned, the original poster, did not follow through with a post that details his fix- if one was found.

I believe I am in the home stretch an if not for the fact that it is pouring rain (In Oregon... really?) I'd be hanging upside down out of the driver's side door of my Blazer.

Note I replaced the Starter relay and the Neutral Safety switch this morning (Echlin parts).

* See above ​

 

[SGT Estum]

You may be past this point already... but if it were me, I would pull the starter relay and bench test it. You can apply voltage with a battery charger set to its trickle setting (2A on mine) and check continuity between the other posts with an ohm meter. Just for kicks, I would repeat the test a second time with the ohm meter probes switched around to make sure you had continuity both directions.

Stranger things have happened.

 

[edpdx]

SGT Estum, I have tried three new relays already, I don't believe in that kind of bad luck. I am now trying to figure out the Purple with white stripe circuit.

The latest twist is that when I fry to start the Blazer, I hear a click and a chirp from under the dash- about where the voltage meter is... maybe lower.

 

[SGT Estum]

If you can get it to crank by bypassing the relay (jumping red and purple wires) but you cannot get it to crank when putting the key all the way forward, then logic would say your relay is not engaging. Possible reasons for this could be (1) bad relay or (2) relay is not getting activated. Bench testing the relay would rule out #1 and leave you with a problem somewhere between the key and the relay (hopefully) and/or between the key and where it gets its current.

 

[rchalmers3]

I am unable to expand the .jpeg diagram you posted. I assume the purple wire that energizes the starter relay emanates from the P/N safety switch, is that correct? If so, then I suggest:

a) Jumper the P/N switch harness. Make a short wire jumper and connect the 24v power in terminal to the purple power out terminal (be safe and make sure it is Ok to crank the starter for this test.

b) if it cranks, look for a broken or mis-aligned switch (see alignment technique). Also follow the purple wire and look for damage or something in the circuit between the P/N switch and starter relay causing an open circuit or voltage drop. BTW, have you measured the voltage available at the starter relay?

c) If it does not crank with the P/N switch jumpered, then trouble shoot the power feed to the P/N switch.

If I am wrong about the schematic and the purple wire goes to the Ig switch, then disregard the above!

EDIT: Have you tried wiggling the shift lever up and down while holding the key in the crank position? You may trouble shoot a non-start due to the purple wire circuit malfunction this way first.

Rick

 

[mistaken1]

If by key on you mean in the 'start' position then you should have 12V on the purple/white stripe wire.

If by key on you mean in the 'run' position then you should NOT have 12V on the purple/white stripe wire.

What happens when you apply 12V to the starter relay terminal that has the purple/white stripe wire? If the relay, the black ground wire and the associated 24V wiring are all good then the starter will engage.

If applying 12V to the starter relay terminal that has the purple/white stripe wire does nothing then run a new known good ground to the terminal that has the black wire and reapply 12V to starter relay terminal that has the purple/white stripe wire.

If you do this and the starter engages then try the key while leaving your new ground wire in place. If no go then trace the purple/white stripe wire. It should only get voltage when the key is in the 'start' position.

Perhaps your ignition switch is bad.