Novak Conversions Jeep Wrangler TJ engine mounts

2005 TJ Starts Occasionally

bjamesvw

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Jan 24, 2026
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Lansing, IL
My 2005 TJ has a 2.4 l 4 cylinder motor with a manual transmission. For years, it has always started on the second try. On the first try, when you turned the key, nothing happened. I would just turn the key to the off position, then the start position, and it would crank and start. Lately, it has been taking up to 10 tries to start (9 tries of nothing happening with the last try it cranking and starting). I have replaced the ignition switch and relay. The electrical connections are clean. I attempted to test the wires at the starter connector, but I'm not sure which wire is the start wire. There are three wires in the starter connector that appear to be Red, Black, and Blue. I can't find a wiring diagram describing where these wires go or what they do. When I turn the ignition to both the start and run position, I always get 12 volts to the red wire. I never get 12 volts to either of the other wires. Does that sound correct? Does anyone know what the three wires do/control?
 
Factory Service Manuals in the resources section have the wiring diagrams. Section 8w.

So does it crank reliably and not start, or does it fail to crank and not start. Important distinction.

Have you verified fuel pressure? Confirmed the ASD relay is hood by swapping it with the horn? Checked fuses? Cleaned battery terminals and grounds?

-Mac
 
The FSM with wiring diagrams is available under resources.

Did you check the ignition actuator pin while you were in there? They are known to break.

Have you checked the clutch safety switch? They are under a recall for the 06, and I believe the 05.
 
Factory Service Manuals in the resources section have the wiring diagrams. Section 8w.

So does it crank reliably and not start, or does it fail to crank and not start. Important distinction.

Have you verified fuel pressure? Confirmed the ASD relay is hood by swapping it with the horn? Checked fuses? Cleaned battery terminals and grounds?

-Mac

I looked at the Factory Service Manuals, and I don't see three wires plus the main battery wire going to the starter.

It fails to crank most of the time. When it does crank, it starts.

I have not verified fuel pressure, but that is not the issue, because it starts when it cranks. I replaced the ASD relay with a new relay and it didn't change. I don't think it will be the fuse, because it does crank about every ten tries. From what I know about fuses is that when the fail, they fail and never work again. The battery terminals are clean. Which ground should I check, just the main off the battery, or are there more.

Thanks!
 
sounds like ignition switch to me . my 05 recently did the same thing. Of coarse right after I got mine fixed my brothers 06 did the same thing. I guess it wanted some lovin' too !
 
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My 2005 TJ has a 2.4 l 4 cylinder motor with a manual transmission. For years, it has always started on the second try. On the first try, when you turned the key, nothing happened. I would just turn the key to the off position, then the start position, and it would crank and start. Lately, it has been taking up to 10 tries to start (9 tries of nothing happening with the last try it cranking and starting). I have replaced the ignition switch and relay. The electrical connections are clean. I attempted to test the wires at the starter connector, but I'm not sure which wire is the start wire. There are three wires in the starter connector that appear to be Red, Black, and Blue. I can't find a wiring diagram describing where these wires go or what they do. When I turn the ignition to both the start and run position, I always get 12 volts to the red wire. I never get 12 volts to either of the other wires. Does that sound correct? Does anyone know what the three wires do/control?

do your gauges move at all when you turn the key and it doesn't crank ?
 
Of course right after I got mine fixed my brothers 06 did the same thing.

🤓

potatohead.jpeg
 
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Hope these wiring schematics from the FSM for your year TJ assist you in resolving the problem.
I would inspect the ignition switch, pin and wiring harness to the ignition switch to verify they are not the problem.


1769349339275.png

1769349379525.png
 
The FSM with wiring diagrams is available under resources.

Did you check the ignition actuator pin while you were in there? They are known to break.

Have you checked the clutch safety switch? They are under a recall for the 06, and I believe the 05.

I replaced the ignition actuator pin about two years ago, but maybe I need to check it again.

I looked at the clutch safety switch, but I'm not sure how to get that connector apart. I'll look into a recall. I did put the transfer case into 4L and I have the additional fuse in, and the owner's manual says that will bypass the clutch safety switch. That didn't help the problem.
 
Hope these wiring schematics from the FSM for your year TJ assist you in resolving the problem.
I would inspect the ignition switch, pin and wiring harness to the ignition switch to verify they are not the problem.


View attachment 668537
View attachment 668538

Possibly I'm missing it on the wiring diagrams, but I don't see three wires in a single connector going to the starter or starter solenoid. Can anyone help me identify the three wires in a connector going to the starter solenoid?
 
Possibly I'm missing it on the wiring diagrams, but I don't see three wires in a single connector going to the starter or starter solenoid. Can anyone help me identify the three wires in a connector going to the starter solenoid?

Please post a picture of the starter solenoid wiring.
Does the wiring appear factory installed or installed by a previous owner ?
Does you Jeep have an aftermarket push button start installed ?
 
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Is there a way to test the ignition switch?

the way I did it was installed a new one and it worked as it's supposed to. so the old one failed the test. And now the one on my '97 wants attention too. If I start it as usual and release the key the radio and fan don't come on, but twist it just a touch and everything powers up.
 
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@CharlesHS you're always johnny on the spot with the diagrams, but how are you doing the screen grab? I looks like you get the full page, like, you're not doing a drag across screen grab. How are you doing that?
 
Thanks everyone for the responses. I feel pretty stupid. I climbed under the Jeep today and the three-wire connector located directly under the starter, does not go to the starter; the correct single wire connector was above the starter and could not be seen.

So I tested the wire at the starter, and I only get 12v at the starter every 5-10 times I turn the key.

I took the ignition apart and the actuator pin looks fine. When I turn the ignition with a screwdriver, it still only starts every 5-10 tries. I did notice that if the fuel pump doesn't run when the key is turned to the run position, then the starter doesn't crank. If the fuel pump runs when the starter is turned to the run position, then the starter will crank. Is there a way to test the ignition switch?

I swapped multiple relays with the starter relay and one relay allowed the starter to crank every 2-3 times but it still didn't start every time. Another relay didn't allow the starter to crank ever. So I don't know if all my relays are bad and some are worse than others or what is going on. Any ideas?
 
Novak Conversions Jeep Wrangler TJ engine mounts