One of my engine control fuses (Fuse#13 I think) keeps blowing causing my truck to stall. My first assumption is its a short in the wiring or some part is shorting the circuit. I was driving about 55 mph on the highway the first time it blew. The next few times it blew was when I was driving slow and turning, like turning into a parking lot. I have a Haynes guide that has a wiring diagram that shows the only wire from this fuse goes into an ECM with a few dozen other wires. My questions for anyone that can help:
1) Do you think its just a wire that is grounding somewhere?
2) How do you find a short? Should I check every wire that comes out of the ECM? Any hints on how to make it easier?
3) Where is the ECM (I can’t find it anywhere in my Haynes guide)?
bump
Most of the wiring diagrams provided by Hanyes, and many others, are mostly worthless and at times incorrect.
Without a factory schematic I can’t be of much help I’m afraid. The factory diagrams will show far more detail, the various connectors, and more accuracy.
A subscription to ALLDATA is a toss-up IMHO. After discovering the ALLDATA diagrams for my daughter’s Mitsubishi were apparently cut and pasted from the also incorrect Haynes manual I’ve thrown in the towel on ALLDATA.
If I’m paying for a subscription I want accuracy; not reprints out of the Haynes or even worse, Chiltons manuals.
About all I can suggest is disconnect the ECM and replace the fuse. Try to do some serious wiggling and squeezing of the wire harness along the way to see if the fuse blows. It’s always possible the main power lead could be chaffed inside the harness and making contact with a wire that goes to ground.
I think the ECM is located next to the heater box near the accelerator pedal. ???
Another possibility would be to see if you could beg, borrow, or steal a copy of at least part of the factory wiring diagram from the official service manual from the dealer.
Feed them a bit of BS. Tell them the truck is 75 miles away on the farm broke down and you don’t want to have it towed that far without making a stab at it first.
I’ve had copies of things run off before with no problem at all during a pinch and most of the time they even refused payment for the copies. Hope that helps.
The wire goes from #13 fuse directly to the ECM 24 terminal. The wire is white / green on the 4 cylinder engine. White / blue on the 6 cylinder.
To check the wire from the fuse to the ECM 24, disconnect the battery, disconnect the ECM electrical connector. Pull the #13 fuse. Use multimeter set on ohms and touch ECM terminal 24 (in connector) with one test probe. With the other test probe, touch the fuse socket. There should be less than 1 ohm. Maintain contact with the fuse socket with one test probe, and touch the engine block (metal) with the other test probe. The ohms should be at infinity. If the ohms are hundreds, or thousands, there is a short in the wire.
High current is blowing the 10 amp fuse. Your Haynes should tell you what ECM 24 is power for. If you know that, you can figure out what outputs it powers. One, or more, of these outputs may be drawing excessive current. Results RSVP.
Thanks for your response. After reading your reply, I did a search and found a PDF repair manual for a 1998 and one for a 2001 Frontier. They don’t have a cover page, but there is some fine text at the bottom of the first page that says Nissan North America…service manual…do not copy reproduce etc. It has some really good graphics showing the layout of the harness. Actual sketches of the truck and at connections numbered and labeled. I think the 1998 is closer to my 2000. This is way batter than my Haynes manual. Thanks!!
Thanks. Very helpful.
What is the url for the Nissan manual pdf you found? If it matches my wiring diagram, you need to check for a partial short from the wiring harness disconnected from the ECM. Set the ohm meter to x1000. Check from the ECM wiring connector terminals #24, 103, 108, 118, 120, to car body/engine ground. If there is any ohms reading, other than infinity, further checking needs to be done.
Then, check from the fuse to ground (should be infinity ohms), and then to the ECM to terminals #24, 103, 108, 118, 120.
Can you tell me how to figure out what # each wire is at the ecm under the dash. Thanks for any help
Kinda old but in deference to being kind to them, the numbers are usually printed on the plug or connector. Magnifying glass and strong light needed. Or the factory schematic would list them and the wire colors.
ECM wiring differs by make, model, engine, and year. The schematic on a 2010 may be vastly differently from a 2011 model.
I can’t help you on this as it will require a wiring schematic.
Not sure what your skill level is in this area but… I would try to run your own wire directly to the ECM yourself. This will involve correctly identifying the wire in question that you are dealing with at the computers plug. Once you verify the wire in the plug using a wire pinout diagram you can then also measure continuity of the suspect wire/pin from the back of the fuse panel to that pin…just to be extra sure you are about to cut the correct wire… yes cut. Once you cut the wire you can then run it directly to the battery with the correct Amp fuse in place and see what happens. If it stays safe and sound you can then make the connection permanent and also determine if it needs to be switched or constant power.
Verification is the key word here… you need to verify you are tracing and cutting the correct wire, so use your head. I know this may sound frightening but its not that hard to do just verify and verify again before actually cutting the wire at the plug.
Once you have done your fair share of automotive wiring, or engine swaps, these things take on much less fear and apprehension. But this task by no means takes that much prior experience to be qualified to take it on. You are simply running a new wire from the fuse box location to the pin in the ecu plug that is the target of fuse #13.
Just a note folks, the original question was ten years ago so solved by now. There was a new poster just asking how to identify the wire number.
The factory service manual will have that information. Unlikely to be found in a general purpose manual like Haynes/Chilton. If you drop by a dealership when they aren’t busy someone there in either the service or parts dept might be willing to print it out for you. Googling is worth a try too, someone may have posted it on a website. If you can’t get the factory service manual info for the connector faces, but you have a wiring diagram, you may be able to figure it out by the wire colors.