Last post on Nov 05, 2013 at 7:31 AM
You are in the Chevrolet Blazer
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Chevrolet, GMC Jimmy, SUV
#403 of 609 Re: 2000 Chevy blazer rear hatch [jlflemmons]
Jul 29, 2009 (4:30 am)
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!
#404 of 609 Re: 2000 Chevy blazer rear hatch [cardoc50]
Jul 29, 2009 (12:54 pm)
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.
#405 of 609 more tail light issues
Aug 02, 2009 (7:29 am)
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.
#407 of 609 Re: 2000 Chevy blazer rear hatch [jlflemmons]
Aug 02, 2009 (12:06 pm)
there are more things than just over current that can blow a fuse
I'm curious. Can you elaborate?
SUVs and Smart Shopper
#408 of 609 Re: 2000 Chevy blazer rear hatch [tidester]
Aug 02, 2009 (5:40 pm)
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.
#409 of 609 Re: 2000 Chevy blazer rear hatch [jlflemmons]
Aug 02, 2009 (7:50 pm)
Thank you for that reply - very informative and helpful!
SUVs and Smart Shopper
#410 of 609 2002 Blazer - Ignition Swith, blown fuse, LED panel
Aug 04, 2009 (2:51 pm)
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?
#411 of 609 Re: 2002 Blazer - Ignition Swith, blown fuse, LED panel [steveo16]
Aug 04, 2009 (3:16 pm)
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.
 On the fuse issue, try turning off the cruise control switch on the stalk, and (considering it is 103 here today ) 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.
#412 of 609 Re: 2002 Blazer - Ignition Swith, blown fuse, LED panel [steveo16]
Aug 05, 2009 (9:14 am)
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