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Starter Relay Working But Not Cranking


NAXJA Forum User
Vernal, UT
I just rebuilt my 2000 and can't seem to diagnose a no crank.

The starter relay is triggering when the key is turned so doesn't that rule out the NSS?
I also have a relay with the cover off that I can manually trigger and nothing is happening. Other known good relays aren't making a difference.

If I bridge the starter it spins, so I confirmed the starter is good. But it doesn't even click to indicate a typical bad starter so that tells me no signal.

There is continuity from the relay pin 2 and there is 12v on pin 3

Getting 0.00 ohms from battery to block and block to body. Tested various spots.

Sorry for another no crank thread... would have piggybacked on the other one from today but my wires aren't severed.
It works when I bridge the solenoid connections just fine. It's a known good starter that I took from the MJ. I'm not even getting a solenoid click, only the relay.
Check fuse 10 (20a) in the PDC. Pin 6 of the relay socket (bottom of the "T") should have 12v. The starter relay is the 2nd from the left. The FSM shows the pins as

10 9 8

Pins 8 & 10 are on the coil side of the relay.

Pin 8 gets 12V from Fuse 19 (10a) in Junction Block with the key in START.

Pin 10 goes to NSS. With NSS in P or N, the NSS grounds and energizes the starter relay when the key is turned to START.

Pin 6 gets 12v from Fuse 10 (20a) in PDC direct from the battery,

Pin 7 goes to the starter solenoid. It passes through connector C108 located under the PDC.

Since you hear the relay clicking, this suggests the coil side is good (NSS is OK).

So check the PDC fuse. If good. Check for 12v at Pin 6.

You can also check for 12v at the small wire at the starter solenoid. Key to START should show 12v.
Here are some results:

I get 12v on pin 6 when 'ON'
I get 12v on pin 7 when 'START'

I get 12v to the brown wire on grey connector (c108?)
I do not get 12v from the PDC to the solenoid
I jumped 7 to the solenoid and get 12v but nothing happens
I have continuity between the blue/black wire and the solenoid
Check the connector at the solenoid.

The brown wire from the relay Pin 7 goes through the C108 connector and then to the solenoid. If you have 12V at the brown wire at the C108 on the PDC side (Key on START), disconnect c108 and check for continuity from the starter side to the solenoid. Make sure the connector at the solenoid is clean and makes good contact. While you have it off, test for 12v with the key to START (relay in). If you get 12V, key at START, then it must be just a bad connection at the solenoid.

You could use a jumper across pins 6 and 7 at the relay with everything else connected (relay out) and it should crank regardless of key setting.
Yep, the connector turned out to be the culprit! Now I feel like a big dummy with that one. Looks like the solenoid-side is damaged. I'll probably convert to a ring terminal.

Now it's turning over, but I'm not seeing oil pressure after cranking (fuel relay and coil disconnected) for a minute or two. Knew I shouldn't have re-used an oil pump...
You should be getting the oil pressure up before ever cranking the motor over. I hope you used a new version of the 0331 head!
This is my 2nd rebuild and I did Cruiser's method the first time with no issues so I kept with the idea of "don't fix what ain't broke". I figure as long as you properly pre-lube then all should be good.

Swapped the oil pump and it built pressure in about 15 seconds. Fired it right up. I used a block and 0630 from a '99 Wrangler. Here's to hoping no more issues!
More progress, indeed! Drove around the block today. Thanks again for the help!