climate control blowing fuse

[mclark]

Hey guys need some help, 94 sho auto climate control fuse blows when i shift to drive . Never had this problem until one day ago the alternator went bad, changed it out and the climate control fuse blows every time i shift from park to drive, or maybe a few seconds after i am moving . I have never had this to happened on an alternator replacement . I did the the self test several times and there was no blinking or codes, only 888 displayed . All the functions work on the climate unit , Could it possible be that the climate unit is bad . Also i have been dealing with hard shift from 1st to second and the trans does not shift into fourth gear . The ole SHO runs good except with the two gremlins that is plaguing me. Any help will be helpful . Thanks

 

[luigisho]

That's a new one. Could be the CC unit or maybe there is a problem with the wiring or alt like regulator or something. Poking around...try this
http://www.explorerforum.com/forums...blower-fuse-blows-when-put-into-drive.245746/

https://www.ranger-forums.com/4-0l-ohv-sohc-v6-tech-33/blowing-fuses-105176/

 

[rubydist]

The fact that it blows when you shift to drive or shortly thereafter suggests that you have a short that is occurring when you move the shifter. That could be related to the shifter itself, or it could be at the other end of the cable related to the mlps on the top of the transmission. I would start looking for a short in those two areas.

 

[pjtoledo]

are you talking about the fuse panel above the parking brake pedal? which fuse?
fuse #9 30 amps feeds the EATC, A/C- heater mode switch, and blower motor
or fuse #17 15 amps feeds EATC blend door actuator, A/C compressor clutch, A/C heater control switch, blower motor speed controller.

hint: A/C compressor clutch is directly underneath the alternator you replaced. look for pinched wires.

this doesn't quite make sense because the A/C clutch gets its power directly from the CCRM, and the CCRM gets its signal from the PCM.

I pulled this info from my '95 ECTM, hopefully a 94 is the same.

 

[mclark]

What is the CC unit , and all that I done was replace the alternator , cant see how any wires was pinched . What is a mlps , I will check it. It is the fuse that is above the brake pedal # 5 or 6 that regulate the backup lights , turn signals and climate control unit. Its just strange when this started happening. I have been driving the SHO for the last six months with no problems with the fuse blowing until I changed the alternator . I was also told to check the trans range sensor as well .

 

[luigisho]

climate control.
manual lever position sensor I think is also referred to as the transmission range sensor on certain cars. Like the links I provided and ruby's post stated, there are wires in the shifter mechanism that can get chafed/worn and exposed to short the circuit. Your best first option is to take apart the interior pieces to expose the automatic shifter and see if any of the wiring is exposed and look at the wiring between the shifter handle down through the floor to where the sensor meets the transmission. As far as pjtoledo's post, he has the manuals and experience to check the wiring schematics and give good insight. Both those guys give very good info consistently. Somewhere in the info posted the chances of finding the answer are very high.

It's not the most common failure we come across but there are logical places to start looking. There is electrical wiring in the shifter for a few things like (never had a GenII auto car so??overdrive on/off maybe on the handle) reverse lights, transmission gear position sensor/mlps wiring to feed info to the computer to let it know what gear you manually selected with the mechanical shifter mechanism, that kind of stuff

 

[pjtoledo]

first off, look at the shifter wires as stated. check the wires from the oxygen sensors too, they join at a splice, go thru a connector, and join a bigger splice before going back to fuse #5.
ok, fuse #5 it is. that runs a butt load of circuits. some go thru a connector under the hood. between the air filter and strut tower is a big square connector, C100 to be exact. that contains daytime running lamps, transmission range sensor, heated oxygen sensors, variable assist power steering module, and remote keyless entry. all run on fuse #5. in that big connector C100, pin #19 is power circuit 298 pink/orange wire. the male side is from the components, female side goes back to fuse #5.
disconnect the connector and monitor resistance pin 19 to ground on the male side and start wiggling wires and moving the shifter. it should not go to zero resistance., that's what blows the fuse.
the daytime running lamps circuit is just a wire going nowhere, but it contains voltage and if shorted will blow a fuse.
the transmission range sensor only uses the power from fuse #5 to run the backup lights (which have a feed to the keyless entry module) and the lift gate (trunk?)relay.

other stuff on fuse #5, multi function switch(turn signal), remote keyless entry module, illuminated entry module, shift lock actuator, instrument cluster-digital, rear window defrost controller, electronic automatic temperature control, airbag diagnostic monitor.

did the fuse start blowing immediately after the alternator replacement? the first rule of trouble shooting is "what was the last thing you did before it broke?"

 

[mclark]

first off, look at the shifter wires as stated. check the wires from the oxygen sensors too, they join at a splice, go thru a connector, and join a bigger splice before going back to fuse #5.
ok, fuse #5 it is. that runs a butt load of circuits. some go thru a connector under the hood. between the air filter and strut tower is a big square connector, C100 to be exact. that contains daytime running lamps, transmission range sensor, heated oxygen sensors, variable assist power steering module, and remote keyless entry. all run on fuse #5. in that big connector C100, pin #19 is power circuit 298 pink/orange wire. the male side is from the components, female side goes back to fuse #5.
disconnect the connector and monitor resistance pin 19 to ground on the male side and start wiggling wires and moving the shifter. it should not go to zero resistance., that's what blows the fuse.
the daytime running lamps circuit is just a wire going nowhere, but it contains voltage and if shorted will blow a fuse.
the transmission range sensor only uses the power from fuse #5 to run the backup lights (which have a feed to the keyless entry module) and the lift gate (trunk?)relay.

other stuff on fuse #5, multi function switch(turn signal), remote keyless entry module, illuminated entry module, shift lock actuator, instrument cluster-digital, rear window defrost controller, electronic automatic temperature control, airbag diagnostic monitor.

did the fuse start blowing immediately after the alternator replacement? the first rule of trouble shooting is "what was the last thing you did before it broke?"

 

[mclark]

It started blowing the fuse the same day i replaced the alternator , before than it was a daily driver for the last six months.

 

[luigisho]

the first rule of trouble shooting is "what was the last thing you did before it broke?"

Always the first thing I think about as well. The shifter thing appears logical as it blows when you engage the the shifter in drive. However maybe that is the last load on a compromised circuit before it pops. Like I said above those are the two places to focus on initially as a cause:effect logical jumping off point. You have to start somewhere and those are the high percentages

 

[pjtoledo]

what happens in reverse? quick jabs on the throttle in park or neutral?

 

[mclark]

what happens in reverse? quick jabs on the throttle in park or neutral?

the car responds well in reverse , quick jabs in neutral and park the car responds well , i would like to apologize for the delayed response, get in late from patrol.

 

[pjtoledo]

that should exonerate the alternator and to some extend the engine rocking and moving wires under the hood.

what happens if you start the engine in neutral and go directly to drive? stay away from park and reverse, even though reverse works.
shift directly to first, not drive? 2nd?

have you checked the voltage with a meter? fuses don't care about voltage, they blow when too much current flows thru them. HOWEVER, more voltage will push more current thru a circuit. so more volts may blow a fuse. that does not explain why it blows only in drive.

 

[mclark]

that should exonerate the alternator and to some extend the engine rocking and moving wires under the hood.

what happens if you start the engine in neutral and go directly to drive? stay away from park and reverse, even though reverse works.
shift directly to first, not drive? 2nd?

have you checked the voltage with a meter? fuses don't care about voltage, they blow when too much current flows thru them. HOWEVER, more voltage will push more current thru a circuit. so more volts may blow a fuse. that does not explain why it blows only in drive.

I will have more time to narrow things down by the weekend , i work 12 hour shifts with one day off .

 

[luigisho]

Those are the kind of hours that forced me to make my SHO a second car and not a primary one to get to work.

 

[mclark]

Hey guys an update, I have driven the SHO for the last two days and no blown fuse as of yet . I don't know which one fixed the issue but I first replaced the alt due to the fact that when I purchased it the outer edge of the pulley was badly bent, so thinking that the alt was good I just swapped pulleys, but the new alt continued to blow the fuse, so I had them to order another one, put it on so good so far, maybe it was dropped and damaged the internals . Second thing was that I found a single black wire behind the alternator that had two small exposed wire cuts about an inch apart, electric taped it up, so far so good . like I said don't know if it was the new alt with the bent pulley or the cuts wires that was blowing the fuse , both was fixed at the same time and no blown fuse so far . Thanks guys for your responses and patience.

 

[rubydist]

maybe the voltage regulator was bad in that alternator that you replaced.

 

[luigisho]

or the exposed wires. Let's hope it's this easy and you're good to go. Post back if it doesn't work or wait a little while and post that it's holding up

 

[mclark]

or the exposed wires. Let's hope it's this easy and you're good to go. Post back if it doesn't work or wait a little while and post that it's holding up

Hey guys everything is good so for , have put almost 200 miles on the Ole SHO, and no blown fuse, if that problem is fixed now I have to deal with no fourth gear, the cars runs good, it accelerates, backup , goes thru all the gears even though 1st to 2nd is harsh with little gas , but 1st to 2nd is smooth when you accelerate but no fourth gear . Down shifts to a stop can really be felt at times, but no check engine light, and I do not have a passing gear . Any ideas before Its taken to the shop for diagnosis . Thanks

 

[rubydist]

There was an issue that some had with the 4th gear actuator not engaging due to a pin coming out or something like that. There was a detailed thread on here about it, so try searching. Or the o/d off button could have a short so it toggles the o/d to off every time you start the car. Otherwise, its likely an internal (expensive) issue.