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Chevy Blazer GMC Jimmy Electrical Problems

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  • diy2diy2 Posts: 2
    As soon as I replace the fuse #15 it blows in matter of seconds no matter what. I don't know any history on the car tho... Any help greatly appreciated... thank you...
  • cardoc50cardoc50 Posts: 49
    ON MY JIMMY,FUSE#15 IS DRL/FOG. WHICH MEANS DAYTIME RUNNING LIGHTS OR FOG LAMPS WHICHEVER YOU HAVE. TO DETERMINE IF THE
    SHORT IS IN THE DRL, PUSH THE PARK BRAKE IN A COUPLE OR MORE CLICKS THEN SEE WHAT HAPPENS. THE DRL'S SHOULD NOT BURN WHEN VEHICLE IS STARTED. IF THE FUSE BLOWS THERE A COUPLE THINGS IT
    COULD BE. YOU BOUGHT THIS VEHICLE USED.WE DON'T KNOW WHAT WAS DONE TO IT EARLIER.CHECK THE REAR OF YOUR HEADLAMPS TO SEE IF ANYONE HAS TAMPERED WITH THE WIRING. IF YOU HAVE FOG LAMPS,
    UNPLUG THEM AND SEE WHAT HAPPENS.IT'SLIKELY THAT ONE OF THESE TWO MAY BE THE BROBLEM..IF NOT, TRY CONTACTING ME AGAIN AND I WILL GIVE YOU SOME INFO ABOUT ELECTRICAL PRBLEMS AND RE-CALLS,
    AND ALSO TSB'S THAT ONLY GM GETS. I CAN SHOW YOU WHERE TO GO ONLINE TO GET THEM.IF MORE PEOPLE WOULD COMPLAIN ABOUT ELECTRIC PROBLEMS ODI WILL MAKE THEM HAVE A RECALL ON THIS TOO
    I HOPE THIS HELPS. GOOD LUCK
  • steverstever YooperlandPosts: 40,448
    Please don't shout - all CAPS is hard to read.

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    Need help navigating? stever@edmunds.com - or send a private message by clicking on my name.

  • diy2diy2 Posts: 2
    Thanks for prompt respond.

    I must admit I jumped to the conclusion, thinking that all the fuse boxes are the same. On my 2000 Jimmy, the Fuse# 15 is 4wd (???). In the manual it's described as:

    "4WD Switch, Engine Controls (VCM, PCM, Transmission)."

    You are absolutely right when you say I have no idea what has been done to the vehicle. One thing that is noticeable is stereo. But how much that can affect 4wd. Got my self Chilton, thou seams there's every important wiring diagram Except the one for 4WD????

    Last time I put the fuse in, and left it idle w/o shifting into a gear, the fuse didn't blow. When I came back to it that night, put it in reverse and drove outta garage the fuse blew. Which makes me think that could be nothing happens "until" you shift and/or into a Reverse?

    I was just about to start unpluggin' things tomorrow. Just not sure where to start. If I would only be able to isolate the thing that would be fantastic...

    thanks again,... greatly appreciated
  • cardoc50cardoc50 Posts: 49
    OK. THIS APPEARS TO BE A VACUME LEAK. THE 4WD SWITCH IS OPERATED BY ENGINE VACUME. IF THERE'S NOT ENOUGH VACUME IT WON'T CHANGE INTO OR OUT OF 4WD. FIRST THING TO DO IS FIND THAT LEAK. SOMEONE MAY HAVE HAD THE TRANNY OUT AND PINCHED OR BROKE THE LINE. YOU MAY HAVE A SIMPLE LEAK IN THE ENGINE COMPARTMENT. CHECK THERE FIRST. YOU CAN USE STARTING FLUID OR SOMETHING LIKE SOAPY WATER IF IT'S RELATED TO THE INTAKE PLENIM
    OR MANIFOLD. SHIFTING INTO REVERSE MAKES THE FUSE BLOW YOUMAY HAVE A GROUND IN THE REVERSE SWITCH OR THE WIRING THEREOF. HAS ANYONE PUT AFTERMARKET BULBS IN THERE? YOU KNOW THE KIND PEOPLE USE WHEN TOWING SOMETHING? HAS THE VEHICLE BEEN IN AN ACCIDENT? SOMETIMES A BODYSHOP ACCIDENTLY WILL SMASH A WIRE IN THE PEOCESS OF REPAIR. IT LOOKS TTO ME THAT YOU ARE GOING TO HAVE TO USE THE PROSESSE OF ELIMINATION IE... TAKE CARE AND TRY ON THING AT A TIME TO RULE OUT DIFFERENT POSSIBILATIES. USE A STETHOSCOPE TO FIND VACUE LEAK ALSO.I WOULD ALMOST BET THOUGH THAT YOU HAVE A GROUND IN THE WIRING AT THE TRANNY OR TRANSFER CASE. I HOPE YOU CAN FIND IT AND IF IT IS A RESULT OF A REPAIR, FIND OUT WHERE IT WAS REPAIRED AND SEE IF THEY WILL ASSIST YOU. SORRY I CAN'T PINPOINT THE PROBLEM WITHOUT SEEING THE VEHICLE.MAYBE SOMETHING I SAID WILL HELP. A VACUME LEAK WILL NOT BLOW A FUSE. GOOD LUCK
  • tberg765tberg765 Posts: 1
    We just bought a 1999 GMC Jimmy and are having electrical problems. We will be driving down the road and the the ABS, Security, Seatbelt lights come on, and also the Gas guage goes to E and the Temp guage goes to 0. Also, the air conditioning with start blowing hot air for a few seconds and go back to cold. Even if the air is off, it will start blowing heat full power for no reason. We just replaced the BCM and that did not fix it. I did notice it is worse when on a bumpy road, or stopping and going a lot. Any help would be appreciated t_berg18@yahoo.com
  • tidestertidester Posts: 10,110
    Please note that people routinely ignore questions accompanied by a request to take the discussion offline. Doing so would deprive others of valuable information and tends to defeat the purpose of a Forum. Our members prefer to share information openly.

    tidester, host
    SUVs and Smart Shopper
  • cardoc50cardoc50 Posts: 49
    The electrical problems you describe on your Jimmy sound like a(or more) wires shorting to ground. I think you should take it to a reputable repair shop.Preferrably
    a Chevrolet or GMC dealer. Ask around and find a good one. The part about it getting worse when you hit bumps almost assures me that something is shorting out.Did you buy it from a dealer or independant person? Can you contact the
    person that had it before you and ask if they had problems with it? These Blazers and Jimmys have had so much go wrong in the electrical system it's almost impossible to determine the source. Sorry I can't help more but,you need to take it to a good shop because I'm sure they have ran across the same thing many times.By the way,do you want to buy a 1997 Jimmy? LOL
  • jlflemmonsjlflemmons Posts: 2,240
    Check the grounding from the negative side of the battery to the engine, and also to the frame/body.

    A poor ground can also yield may bizarre symptons.
  • cardoc50cardoc50 Posts: 49
    Sorry Steve about the caps. It won't happen again.Thank you
  • chewchangchewchang Posts: 2
    my alarm goes off every 2 or 3 hours.and my inside light stays on inless the dome overide swicth is pussed in,any ideas?
  • potter67potter67 Posts: 2
    my drivers side window stopped working. checked fuses (ok). does not make any
    sound when button is depressed. Is window motor gone. How do I trouble shoot the problem? :cry:
  • rw2rw2 Posts: 2
    2000 Chevy Blazer ZR2, power door locks, remote mirror controls & electric rear hatch release are not operating. Unable to open rear hatch/tailgate.
  • cardoc50cardoc50 Posts: 49
    I do know the hatch,door locks and mirrors are on the same circuit. If you have checked the accesory fuse(Ibelieve that is the one), It would be the relay. The
    problems you have with those is that they draw a lot of power to operate. That's why there is a relay also and not just a fuse. If I remove the power accesory fuse,those same things do not work at all. I hope it is the fuse because I don't know exactly where the relay is. From 1995 to 2004 they made a lot of small changes. Your owners manual should help you find the relay if you find the fuse is good. I'm crossing my fingers and hoping it is the fuse. I hope this works for you and good luck.
  • rw2rw2 Posts: 2
    I want to thank cardoc50 for this information. I was able to find the relay center which is next to the windshield washer reservoir on the drivers side engine compartment. I replaced the fuse there and hatch,door locks and mirrors are now working.
  • jlflemmonsjlflemmons Posts: 2,240
    Glad it was just the fuse. One thing that folks don't often realize is that it isn't the electricity per se that pops the fuse. The fuse has a specific (very low) resistance, and the more current that goes through, the hotter it gets. A short circuit will cause a very fast rise in temperature in the fuse element, and 'pop goes the fuse'. I mention this because in intense summer heat, you can pop a fuse from the combination of the temperature rise caused by electrical current added to extreme underhood temperatures.

    This was very common on the fan blower circuit used in GM back in the '60's through 80's. In the middle of a really hot summer day, the high speed would quit working on the a/c, but all the other speeds (different fuse) would work.
  • cardoc50cardoc50 Posts: 49
    RW2 thank you for the nice words. I have been a mechanic for Ford motor company and General motors for 38 years. I am not a genius but heat from air temperature rise will not blow or (pop) a fuse. And did'nt you say you had a 2000
    model Blazer? Not a 1960 Chrysler? Just glad I could be of help and thanks again.
  • jlflemmonsjlflemmons Posts: 2,240
    No, the heat underhood alone will not pop the fuse. But the high underhood temps combined with a fuse element heated by it's rated current can definitely blow a fuse. Electric current is what causes the temperature to rise in the fuse element. When it gets hot enough, it melts and opens.

    The same issue can occur with automatic resetting circuit breakers, such as on some headlamp circuits. The breaker will trip, and reset when it cools down. Many years ago I was called down to Houston where a prototype industrial truck was undergoing environmental testing. Seems they were tripping the breakers for the AC unit cooling the instrument cab. Current monitoring showed they were only at 80% of the circuit breaker rating. But they were testing inside a heat chamber, and the combined effect lowered the capacity of the breaker.

    This was very common on GM back in 68 -76. Happened all the time when the Houston area temps went up into the 100 range. Folks would hop in their cars after work, start the car, flip the AC on high, and in about five minutes the high blower fuse would pop. Car would come to the shop and there would be nothing at all wrong with the blower. The high speed blower fuse was a separate inline fuse holder back behind the aircleaner on the firewall. We would routinely move the holder over to the low side of the AC drier and attach it there. Problem solved, the freon line would keep the fuse cool.

    This isn't just a car issue, this is common to all passive circuit protection devices. They are tripped by heat caused by electrical current. Automotive and industrial fuses are rated at 25C, as is the AGC30 that was typically used on the high speed blower circuit. More than one blower motor has been changed thinking it was the cause of the blown fuses.
  • cardoc50cardoc50 Posts: 49
    Sir, if you knew the answer to R2W's question,you should have gave him a simple answer to his simple question not ramble on about 60 model cars. Todays vehicles are designed to use thinner engine oil and run at much higher temperatures. Thermostats right at almost 200 degrees. If engine compartment heat can blow afuse ,there would be cars sitting by the highway everywhere. The gentelman had a 2000 year model that is designed to operate at extremely high temperatures.You keep refering to cars built 40 years ago. It is what it is! I get on here to try to help people,not argue. Thak you and have a great day!
  • jlflemmonsjlflemmons Posts: 2,240
    Cardoc50,

    I am not trying to argue with anyone here, just pointing out that in my 40+ years of working on electrical systems in both automobiles and industry that there are more things than just over current that can blow a fuse. I am glad your expertise was of good use to him, and I am glad his problem is resolved. My apologies if I have offended you.

    jflemmons
  • so i started reading through the forum pages to see if any one else has had the problems i have had with these lights and after reading quite a few pages, i figured i would just post a thread, so i appologize for being redundant. so im working on a 95 jimmy 4 wd 4 door. the runnig lights work fine (head lamps, hi and low, parking lamps, front and rear) but the insturment lights are out, the brake lights dont work (including high mount) and no turn signals work at all including the 4 ways. i know the brake switch works because it kicks the cruise controll off when you hit the brakes, and when you hit the turn signal lever to signal left or right it sounds like the flasher lets out one click, but no lights light up. it could be a circuit breaker and not the flasher though. all the fuses on the left side dash are fine and there is no power to the signals at the sockets, so its not a ground issue. if some one could give me an idea of whats wrong that would be great, i dont want to have my buddy spend 250 on a multi function switch if it could be something else. thanks for your help.
  • tidestertidester Posts: 10,110
    there are more things than just over current that can blow a fuse

    I'm curious. Can you elaborate?

    tidester, host
    SUVs and Smart Shopper
  • jlflemmonsjlflemmons Posts: 2,240
    Sure. Things like a loose fuse holder. Causes an increase in contact resistance, and more heat. Fuses are blown by heat, whether caused by excess current, ambient temperature, or high resistance in the fuse holder itself. Not uncommon to see a fuse blow when a cheap inline holder is used on a high current circuit. Sometimes, if the fuse is rated high enough, the holder itself will melt before the fuse does. All fuses have a specific resistance (very low, but exact) so that when the rated current is reached, the resistance will cause a rise in temperature of the fuse element and cause it to melt. In the case of, for example, an ATC30 automotive fuse, the melting point/time varies by the current applied. At 30A, it will get warm, but maintain integrity. At 35A, the heat will rise to melting point in 10sec, 40A in 5sec, and 80A in 1/2 sec. A dead short from a high current source (ie: the battery) will melt the fuse pretty much instantly. But if you are running at 30A, and with a poor fuse holder contact, the additional rise in temperature applied to the blade of the fuse will lower the current capacity of the fuse. Also, unless otherwise specified, fuses are rated at 25 degrees C, so if you are pushing the limit of the fuse at sub-freezing temps, summer temps will most likely cause the fuse to melt.

    In an auto-resetting circuit breaker such as used in a headlight circuit, the same principles apply. When the temperature of the circuit breaker reaches a pre-designed point, the circuit path opens, causing a cool down. Once it cools down, it closes the current path and will repeat the cycle until the fault is corrected.

    A really neat trick is to SOLDER a low current fuse into a circuit without "blowing" the fuse. Which is why Bussmann/Cooper always advises to solder inline holders before installing the fuse.

    Not so much with automotive applications, but in industrial apps a poorly mounted fuse block can open a fuse through vibration.
  • tidestertidester Posts: 10,110
    Thank you for that reply - very informative and helpful! :)

    tidester, host
    SUVs and Smart Shopper
  • I am having a problem with my LED panel lights (Shift position indicator and odometer). When my ignition switch is in the RUN position, the shift position indicator, odometer and radio stop working. When the key is turned back to the OFF position, they all work fine. When the key is turned back to the LOCK position and pulled out, the radio is still on. Also, the 10amp "Cruise Control Module and Switch, Body Control Module, Heated Seats" fuse keeps blowing out and the temperature gauge does not appear to be working.

    Is this an ignition switch problem or something worse?

    Are all of these problems related or is it more than one problem?
  • jlflemmonsjlflemmons Posts: 2,240
    Wow, quite a list of symptoms there. How many miles are on the vehicle? Some of what you list sounds like a bad (worn) ignition switch, but I would have to look at a schematic to see why the CCM fuse is popping. There may be two issues at hand.

    I have a basic schematic set on this vehicle, let me check it and get back with you.

    [edit] On the fuse issue, try turning off the cruise control switch on the stalk, and (considering it is 103 here today :surprise: ) don't turn on the heated seats. Put in a fuse and see if it pops immediately. If not, turn the switch to run and check fuse. See if the indicators in the instrument cluster come on. If still good, turn on the cruise switch. Try and isolate what function is drawing the high current.

    I don't have the complete schematic available, but I believe the functions in the instrument cluster that you listed as malfunctioning all come from the BCM, and the radio has aux power that (I believe) is also supplied by the BCM for the delayed power off function. The cruise control used to be a simple system, but I am thinking it also has a tie-in to the BCM.

    Try the tests I listed above and tell us what you get.
  • cardoc50cardoc50 Posts: 49
    Check the oil pressure switch on the left side of the engine first. The temp switch
    and oil pressure switch are wired so that when one goes it appears that they both
    go out. As far as the other problems I don't think they are related to temp guage.However, I've been wrong before. The other problems and possibly all the
    symptoms may be because of the ignition switch.Have you had it checked for trouble codes? I really don't know if I can be of any help at all. Check oil pressure switch and temp switch. Borrow a code scanner or take it to a repair shop to see
    what codes (if any) show up. GM did a lot of wiring changes to that body style
    between 1995 and 2004 because of electrical problems. Sorry I can't help.When you get it fixed,can you tell us what the problem(s) were? I'm curious.Thanks
  • Thanks. Those sound like good places to look. It doesn't have heated seats, that is just what the manual says is on the circut. Could there be loose wires for a heated seat that are shorting out?

    Also, where can I find the Body Control Module and how can I test it?
  • jlflemmonsjlflemmons Posts: 2,240
    Not likely on the seat wiring. The BCM is under the dash to the right of the gas pedal. Other than replacing it, there isn't much you can do with it. A dealer can run diagnostics on it, but that isn't something most users would have the tools/software to do.

    I would look first to the ignition switch. Were you able to determine what function was blowing the fuse?
  • i have a97 gmc jimmy my fuel gage would only work part time i had a new fuel pump and sending unit installed it worked for about a week now it doesn't work at all .I pulled the tank down checked all the wires at the tank all seem good A friend of mine also has the same problem.Any ideas on where to check ?? I checked the fuse for gages it was good.any thoughts would be appreciated.
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