Ok... now MY truck won't start

In the last two weeks my '06 6-Speed has been doing the intermittent no start thing. Can someone help me diagnose it?

* Dash lights all light up.
* Engine does not spin
* There's no solenoid click whatsoever.
* Battery terminals are clean and always have been.
* If the cabin air fan is running, the fan dies when I turn the key
* Battery water was a bit low in each cell, but not by much. I added a little water to each.
* After the 3rd to 6th try, she starts powerfully and just fine.
* No CELs
* 30,000 Miles

Battery, clutch pedal interlock switch? Thanks.

I looked at the pedal area and the rubber grommet/stopper is in place. I see that there are TWO clutch switches down there in my 4x2. There's a switch at the top that's normally depressed when the clutch pedal is not being pressed in and there's another switch at the bottom that's depressed when the clutch is depressed.

I got on the Courtesy Parts website and am confused because they show two "Clutch Pedal Position" switches:

25325-D40003 @ $16.34 Ea

32325-D40002 @ $84.08 Ea

The parts diagram shows only one switch, but the written listing of all parts shows two switches and there are no photographs of either one. Sigh.

I disconnected the bottom switch and tried to start the truck and it exhibited the same traits as when it won't start, so that may be my culprit. I just wish I knew which P/N to order. Do you have the P/N that was replaced in yours?

Oh, about battery water. You can easily pry the caps off the battery and see the water level inside and the owner's manual has directions on what level to maintain.

Thanks for your help!

I removed and tested my clutch switch and it's fine. As best I can figure, the two clutch cancel switch relays are for 4x4 6-Speeds and don't apply to my 4x2 6-Speed. (I cannot find the relays; I don't have a clutch cancel switch.)

Advance Auto tests my battery as "Marginal" on their sophisticated machine. AutoZone tests my battery as a bit weak, but okay on their simpler machine.

I even drove to a Nissan Dealer and asked a service writer, but he wasn't aware of any common flaw on Frontiers that might cause this.

I've noticed that on the occassions when it won't start, if I continue to hold the key in the start position (with everything in total silence), in about 5 to 7 seconds she'll instantly fire up good and strong as if nothing's wrong.

I'm thinking about replacing the battery so as to eliminate it from the list of potential bad actors. I'd hate to waste a $100, but the battery will likely need replacing sometime within the year anyway.

Intermittent problems are a PAIN aren't they? Ideas welcome! :-(

Thanks Clint. Ground connection is okay. I worked my way through the service manual this morning and I intermittently failed the "Power Supply For Magnetic Switch" test.

That leaves seven potential culprits and I can rule out three of them (Fusible Link, Fuse and Clutch Interlock Switch). The remaining four are Ignition Switch, Starter Relay (in IPDM), Starter Relay Request ON Signal or a bad harness. I'll bet it's the IPDM and I just read on the Nissan TSB site that the whole thing must be replaced. At least it shouldn't be a terribly expensive part. I wonder if it's covered under the powertrain warranty?

At least this might help the Nissan Tech determine what's wrong if my truck decides to be sweet and start up every time when it's at the shop.

I'm going to look in the service manual and see if there's an ignition switch test. I was able to hotwire my '80 Honda within minutes when it's ignition switch went bad, but something tells me that testing an ignition switch these days will be much more difficult.

Thanks again for your suggestion.