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Chevy Blazer GMC Jimmy Electrical Problems

607 messages,  Last post on Mar 25, 2013 at 5:45 PM

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Messages Page 41 of 61

#398 of 607 Re: 2000 Chevy blazer rear hatch [rw2] by cardoc50

Jul 27, 2009 (5:45 am)

Replying to: rw2 (Jul 24, 2009 9:41 am)
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.

#399 of 607 Re: 2000 Chevy blazer rear hatch [cardoc50] by rw2

Jul 27, 2009 (2:01 pm)

Replying to: cardoc50 (Jul 27, 2009 5:45 am)
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.

#400 of 607 Re: 2000 Chevy blazer rear hatch [rw2] by jlflemmons

Jul 27, 2009 (4:00 pm)

Replying to: rw2 (Jul 27, 2009 2:01 pm)
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.

#401 of 607 Re: 2000 Chevy blazer rear hatch [jlflemmons] by cardoc50

Jul 28, 2009 (4:18 pm)

Replying to: jlflemmons (Jul 27, 2009 4:00 pm)
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.

#402 of 607 Re: 2000 Chevy blazer rear hatch [cardoc50] by jlflemmons

Jul 28, 2009 (10:04 pm)

Replying to: cardoc50 (Jul 28, 2009 4:18 pm)
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.

#403 of 607 Re: 2000 Chevy blazer rear hatch [jlflemmons] by cardoc50

Jul 29, 2009 (5:30 am)

Replying to: jlflemmons (Jul 28, 2009 10:04 pm)
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 607 Re: 2000 Chevy blazer rear hatch [cardoc50] by jlflemmons

Jul 29, 2009 (1:54 pm)

Replying to: cardoc50 (Jul 29, 2009 5:30 am)
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

#405 of 607 more tail light issues by custom_scout

Aug 02, 2009 (8:29 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 607 Re: 2000 Chevy blazer rear hatch [jlflemmons] by tidester

Aug 02, 2009 (1:06 pm)

Replying to: jlflemmons (Jul 29, 2009 1:54 pm)
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

Messages Page 41 of 61

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