I have a problem with my #5 fuse blowing, checked the components Chilton's claims run through that Fuse, no joy. Does it intermittently, but is assured to blow again within 10-15 mins of replacing it. Takes down the blinkers, A/C control unit etc etc.. tried everything within my limited knowledge, please some one save me from this summer heat!!!!
Fuse #5 Keeps Blowing 91' SHO
- Thread starter elchado
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
NiNeTy Fo SHO
No-mo-SHO Man
I had this problem on my old SHO...I found a few (aka, 1 or 2) other people who had the same issue. Never figured it out.
Once piece of info...fuse 5 also controls the pre-heating of your O2 sensors...in the winter time you will get a CEL until the car warms up and then it will shut off (cause the O2's are then heated up by the engine).
It takes down blinkers, EATC (which I re-wired to another fuse so I would have heat/defrost), reverse lights, rear defrost, and not in the manual, O2 pre-heat.
One thing I did notice...I could replace the fuse and with the car in accessory mode and not started, everything would work...tried it out for 15+ minutes with all items on...started the car, and boom there went the fuse. I think it has to do with the O2's as I dont think they would be pre-heating without the car running. I checked wires, replaced both O2's and still blew.
Once piece of info...fuse 5 also controls the pre-heating of your O2 sensors...in the winter time you will get a CEL until the car warms up and then it will shut off (cause the O2's are then heated up by the engine).
It takes down blinkers, EATC (which I re-wired to another fuse so I would have heat/defrost), reverse lights, rear defrost, and not in the manual, O2 pre-heat.
One thing I did notice...I could replace the fuse and with the car in accessory mode and not started, everything would work...tried it out for 15+ minutes with all items on...started the car, and boom there went the fuse. I think it has to do with the O2's as I dont think they would be pre-heating without the car running. I checked wires, replaced both O2's and still blew.
Last edited:
shoon
cliTaurus
I would start by unplugging everything on that circuit.
-VAPS module (if equipped)
-EATC
-O2 Sensors
-Multi Function Switch
-Air bag Diagnostic Module
-Rear Window Defogger
Once everything, or most of everything is unplugged see if your fuse pops again. If the fuse does not blow, start plugging things in 1 at a time, until it does blow, and that should help pinpoint where the problem is.
-VAPS module (if equipped)
-EATC
-O2 Sensors
-Multi Function Switch
-Air bag Diagnostic Module
-Rear Window Defogger
Once everything, or most of everything is unplugged see if your fuse pops again. If the fuse does not blow, start plugging things in 1 at a time, until it does blow, and that should help pinpoint where the problem is.
I'm having trouble finding the VAPS module, AB Diagnostic Module and the harness for the MFS, I took apart part of the column shroud but couldn't see where it plugs in (MFS), but then again I didn't completely tear into it. I tried the 02 sensors, illuminated entry actuators and went to a salvage and picked up another EATC and no joy there either (although the new one is much prettier, i.e. no broken buttons). If i rewire the EATC to another fuse will that make the AC work? Is it possible to re-wire any of the other components? Just really irritating knowing that the AC works amazingly well considering its almost 20 years old, I miss it 
Last edited:
38SHO
#1 Oil Abuser
with fire extinguisher at your side, try a bigger fuse... instead of popping the fuse so easily it will start melting the wire if its got a short... follow the smoke
or route in a circuit breaker on the fuse panel..... so u don't keep reusing fuses
the MFS wires, I believe, are on top of the column back around where the 4 way flasher hazard switch is about.... I had a problem with my turn signals screwing up and blowing fuses, I don't know if this is the same circuit as the problem you have, but it turned out to be my reverse light wires off the transmission got into the clutch cable and when I pressed down on the pedal it blew the fuse...
look for something that is common when you blow the fuse, like what are you doing, shifting gears? turning on something particular? for me it was when I pressed on the clutch pedal..... once I figured that out... it really narrowed down where my problem was
I can't tell you exactly what the cause is, because that would focus you in a the wrong direction probably... because it could be a lot of different things wrong DO NOT NARROW YOUR POSSIBILITIES.... i can just guide you and open up your eyes to help you narrow down the problem, then you can look in that area more specifically for a shorted wire, bad component, or such...
or route in a circuit breaker on the fuse panel..... so u don't keep reusing fuses
the MFS wires, I believe, are on top of the column back around where the 4 way flasher hazard switch is about.... I had a problem with my turn signals screwing up and blowing fuses, I don't know if this is the same circuit as the problem you have, but it turned out to be my reverse light wires off the transmission got into the clutch cable and when I pressed down on the pedal it blew the fuse...
look for something that is common when you blow the fuse, like what are you doing, shifting gears? turning on something particular? for me it was when I pressed on the clutch pedal..... once I figured that out... it really narrowed down where my problem was
I can't tell you exactly what the cause is, because that would focus you in a the wrong direction probably... because it could be a lot of different things wrong DO NOT NARROW YOUR POSSIBILITIES.... i can just guide you and open up your eyes to help you narrow down the problem, then you can look in that area more specifically for a shorted wire, bad component, or such...
Grantorinslo
New Member
Just like 38SHO said, my friend ran into the same problem, one of the harnesses (green arrow) runs underneath the clutch cable and is tied in to the MFS/Fuse #5 circuit. If the pins that hold the harness in place are worn it will wind up resting between the clutch cable and a bracket (red arrow). This probably won't be your issue, but it has worked for 2 people so far, and 38SHO would make a third that experienced the same issue. To check it undo the harness connector (grey plug) and look for wear spots on both sides where it close to the clutch cable or bracket. If the tape is worn you should remove it and check the wires. The one that we found worn was the black/orange stripe wire that goes into one of the corner pins on the connector and it solved the fuse issue.
The wire - note you can barely see the copper. I couldn't tell this was the short until we removed the harness wrap.
Good luck and I hope this helps, or at least eliminates a possibility.
The wire - note you can barely see the copper. I couldn't tell this was the short until we removed the harness wrap.
Good luck and I hope this helps, or at least eliminates a possibility.
shoon
cliTaurus
VAPS module is located below the steering column, on the right side. If you remove the kickplate with the 4 torx screws you should see it in the lower right corner with a bunch of other modules.
ABS Controller (not sure why the book said diagnostic module) should be top right corner, just to the right of the rad. to the right and below CCRM module.
ABS Controller (not sure why the book said diagnostic module) should be top right corner, just to the right of the rad. to the right and below CCRM module.
