Ok guys this is a long complicated one. So last year I wasn't able to start my car and was told it was my fuel pump from a small local shop. I replaced the pump and the car worked for about a day and then same thing...no start. So I take it into the dealer and they say it needs a new IMMU system because somehow it went bad. I paid around $800-900 to replace the system.

Right after I got it back I had some similar problems with starting, I would have to turn the key multiple times and then it would work.....now this was on a off but was pretty random.

Then about 3 weeks ago I had the same issue with a no start. I checked everything and then got it towed. Nissan again diagnosed it with a bad IMMU as well as an electrical code string. So they again replaced the IMMU but under warranty. So I get the car home. Go out one time to the bank and then back. Go to start it for work about an hour later and the same problem. So I tow it back to Nissan and they have it for about 2 weeks diagnosing it as some electrical problem. I went down to the dealership Friday and they say it's my electrical harness and that it has too much resistance going through it and it is frying the IMMU and supposidly the ECU as well. They quote me about $5000 and say basically the car is a total loss. They say both wiring harnesses must be replaced as well as the ECU and IMMU system. Here is my question however:

I did put some after market mods on the car but it was minimal and quite a while back. I had done the fog light rewire, blinker mirror lights, speakers, and new headlight harnesses. Would any of this "decay" or cause significant irreverasble damage to the wiring harness? How would I go about fixing this by myself? If in fact the IMMU is dead again couldn't I just remove the IMMU unit and possibly get a used 98 ECU that wouldn't prevent the car from starting without IMMU codes? What is the best possible course of action aside from parting the car out or taking it as a total loss?

I really need a TON of help here from anyone that can help. Thanks!

 

on the new $5000 dollar harness issue.
I bet your ignition switch is shot. It's a common failure item on 4th gens.

A complete wiring harness for the car runs about 1200 bucks and takes about 6 hrs to install. I've done many on 5th gens at the body shop because of headlight theft destroying the harness and the front impact sensor. By law, if the SRS system wiring is damaged, it must be replaced, not reapired. The harness for your 4th gen might even be cheaper, but it ain't no where near a $5000 dollar repair and honestly I think your dealer doesn't know what their doing. From reading your post, it's obvious they have yet to diagnoss the problem correctly. Wiring doesn't simply go bad and this forum has yet to see such an issue. My vote goes twards your ignition switch and get your car out of that dealership. They are idiots.

 

Yeah +1 on your ignition switch. They are prone to going out on 4th gens and the symptom is nothing happening when you turn the key, you would have to turn it multiple times in order to get the car starter. This is because over time the solder points get bad and cause issues.

A new ignition switch is $15.00 and takes about 5 mins to replace. Pop off the lower cover of your dash pop off the plastic piece around the steering wheel. Two more screw and unclipping and clipping a harness and you're set.