Fuse number 4 in the fuse box under the dash blows randomly. The fuse is a 7.5 amp fuse labeled Ecu/Cruise control.

The fuse will blow at anytime, especially once the Ecu is cleared of all codes. Right before the check engine light comes on (Due to 2 faulty ho2s) A faint click is heard and the fuse blows. I have been monitoring the fuse via the cruise control master switch just left of the steering wheel.

I have checked every possibility I have read about and or have pondered about. Grounds, alternator tested, Eld solid, wired stereo to battery terminal ( supposedly this could blow that fuse, even though its entirely separate circuit) My last guess would be the ignition or transmission.

Before this issue started the head gasket delaminated. I replaced the head gasket/ intake gasket/ timing belts/ idlers/ water pump. Car sat for a bit during the overhaul. When I put the car back on the road I ran the battery flat. Once I realized what happened I replaced the fuse and tested the alternator. Loaded 14.15 volts unloaded 14.50 volts. Ran fine in the driveway ac on, blower on high, radio full volume, high beams on. As soon as I hit the road no more then 10 miles it blew the fuse. I replaced a junky ground off the left motor mount and drove 100+ miles before it blew again.

I started getting really annoyed and tried anything and everything to get it blow. Today I really messed it up. I re routed the 12 volt constant for my radio to the fuse panel under the hood ( bought a fuse holder a wired it the hot battery terminal ). No success, still blew randomly while driving. While sitting in a parking lot with the car running I left my headlights on and turned the radio up; I began to shake the key in the ignition for a good 10 minutes watching the cruise control master light. Nothing, fuse didn't blow. Not until I started driving again. Now it blows every 10 seconds. I drove 15 miles and replaced the fuse 3 times. I can't even get it not blow by turning off accessories. It almost seems like I have found the problem. Maybe it is the ignition all along. I was more curious as to what else could cause that fuse to blow in that fashion, so after a process of elimination the ignition had to be checked. Why it would fail after sitting for 6 months. Fk if I know.

On top of that, I have had transmission problems for as long as I can remember. I have read this could also be the culprit of the blown fuse. Being apart of the cruise control system it only makes sense. I have a torque converter issue, has trouble locking. Searches endlessly. Never really concerned me as long as it shifts. lol Before I did the head gasket I had a torque converter/clutch circuit malfunction dtc. I have NOT seen this dtc in over 500 miles. Strange aye? Either the torque converter is toast or the solenoid is. Never has this caused a blown fuse, but I would hate to overlook it.

It does seems very stiff. Shifts like a sore c**t, hard to put into reverse. I actually back off the throttle now because it shifts so hard. Because the problem is so intermittent, I have a hard time ruling this out. What does shift solenoid A and B play a role in this circuit? I am not sure. President not sure.

So as you can see I am f/n clueless as to what is causing the surge in voltage across fuse # 4. I am about to stick a 30 in it and let the damn car burn..... but that isn't the right idea. lol

I doubt a ecm/pcm issue, Unless someone knows that the computer is the issue. Seems to be functional.

I have located the Electronic Load detector which is inside the fuse panel located under the hood. Connections solid, plus all chassis grounds are solid as well.

The rate of blown fuses has increased exponentially after molesting my ignition with the key. The ignition is apart of the charging circuit and could blow the number 4 fuse. I hate to be a parts changer but this is my last guess.

I am going to upload the schematics Courtesy of alldata.

 

Here are the components that draw power from that fuse (based on the 94 accord wiring diagram).

Charging system light
Cruise control main switch indicator light
Cruise control unit
Alternator
EGR control solenoid valve
Transmission computer
Engine mount solenoid valve
ELD unit
Radiator fan control module
Fuel injection air solenoid valve (only on vtec engine)
Intake air resonator control solenoid (only on vtec engine).

Have you done any work near any of these components?

You can try unplugging some of these components one at a time to determine the short. Atleast inspect the wiring.

 

Are you sure the wiring diagram is the same? I have a Ecm/pcm, earlier hondas have a separate computer for their automatic transmissions. Mine does not have a separate unit, is that the transmission computer you're referring to?

I had the head out of the car, working in, out, and under the car. It is very plausible I could have tampered with some connection.

I have inspected every visible piece of harness and connector.

Charging system light? In the dash I presume?

I do not know where my cruise control unit is located, nor do I know where an EGR Control solenoid valve, engine mount solenoid valve. Will see if it is shown in the numerous pictures alldata has of my car.

My engine is a non vtec so the other solenoids are not relevant.


Still having issues extracting schematics from it though. trying to do so many things at once.

 

I disconnected the EGR and engine mount solenoid valve with no effect. When I discoed the EMS valve as soon as It shifted into it reverse it blew.
I reconnected that solenoid, and discoed the EGR valve. All seemed well at 12 am, went up my dead end road. Turned around, half way back it blew again.



Charging system light <--- What and where can I find it?
Cruise control main switch indicator light <----- where can I find it?
Cruise control unit<--- I have tested and operated the cruise control trying to blow the fuse, doubt it. Never blew the fuse once using cruise, leaving the master off does not make any difference either.

Alternator<---- Spin tested..... Should I still be considering this the issue?

Transmission computer<----- How do I go about this?

ELD unit<---- If this is discoed how do I charge my battery? Defeats the test altogether since I am only concerned with it not charging the battery.

Radiator fan control module<--- With this discoed how do I test this intermittent problem without the car overheating?

 

I think that this will be tough to track down with a volt meter. I don't have a wiring diagram that lists everything that draws power from that fuse on an OBD2 96/97 accord.

Does the charging system light turn on when you turn the key to the II position, but do not try to start the car?

I would carefully look at the wiring for the alternator for worn insulation that can ground to metal. I would consider pulling the alternator and have it bench tested at a parts store. It may be putting out the proper voltage, but could be shorting out.

 

The only addition to the components protected by the No. 4 fuse for the 96 was the EVAP purge control solenoid valve.

The supplement service manual for 96 should be available for download as part of the links in the sticky above in this forum section.

 

Charging system light turns on, as long as fuse # 4 is good.

Alternator was spin tested? don't know if that would be the equivalent. She did get soaked in power steering fluid :/ Dielectric I hope?

 

Discoed the Evap valve, Made it the end of my dead end road, blew as I turned the wheel.

I am really starting to think its in the harness... which really sucks.

 

Disconnect the alternator, drive the car, and see if the fuse blows.

Wild *** guess: Power steering fluid partially shorting alternator diodes causing excessive AC ripple which causes the fuse to blow.

 

Wild *** guess was right. Not sure if that was exactly what was blowing the number 4 fuse but it was the alternator. Thanks for the help everyone.

Note: Do not trust a spin test at advance auto. Diagnosis yourself