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2005 chevy trailblazer_ls
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Discussion Starter · #1 ·
Hi all. New member here with a pretty strange problem.

I have a 2005 Trailblazer LS. We have not driven it at night for quite some time before last night, so I am unsure when this problem may have started.

Last night we were coming home after dark, and when the high beams were turned on, the engine stalled out and died. After turning the ignition off for 10 seconds or so, it started back up normally (had the low beams on at this time). Every time we put the high beams on, the engine would stall out, so we drove home with low beams only.

Messing around with it today, I noticed a few other things as well.

When I start it with low beams, both headlights are normal intensity, but when I go to high beams, the driver side light gets very dim (the pass. side goes to high like normal) and the engine starts to stall.. Then, when I go back to low beam, the driver side still stays dim (the pass side acts normal), but the engine will recover and run normal. The driver side light will stay dim until I turn the ignition or switch off for about 10 seconds or so. After that amount of time, both low beam lights are normal when turned back on.

One other thing is when the headlights are normal, both blinkers work normal, but when I get the driver's to go dim, the left blinker flashes extremely fast (the right blinker works fine at all times).

Anyone heard of this happening or have any ideas? Thanks for any help!
 

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2004 gmc
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Sure sounds like problems in that high beam circuit. Do you have a meter and some experience using it? At least go behind the headlight and start looking for mice nests and chewed-off wire insulation.

Also, if there was enough current draw to stall the engine, a the high beam headlight fuse would certainly have blown. I'd yank fuses 2 and 5 to isolate the high beam circuits, and see if it still stalls out and affects the blinker. Do you have a lot of corrosion in there that may affect your headlight area ground wires?
 

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2005 chevy trailblazer_ls
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Discussion Starter · #3 ·
Thanks for the speedy reply. Got a few updates.

I must have messed around enough times because now the driver side low beam will not come on with normal intensity.

Earlier, I was just shining the lights against my garage wall and didn't look at the lights from the front of the truck. This time I went to the front and found that when in low beam mode, all 4 bulbs are lit. The drivers side are both dim and the pass. side low beam is normal while the hi beam is glowing dim. With the engine off, if I go to hi beam, the drivers side both stay dim and the pass side hi beam gets bright while the low beam bulb glows dim.

I tried isolating the high beam system by pulling the fuses (2 & 5). With the engine running, pulling either fuse will kill it. Doesn't matter if the lights are on high or low, the engine still dies when pulling either or both fuses. My Chilton manual shows that both fuses get their power from the hi beam relay, so I pulled that and the engine stays running.

I metered the plug on the driver's side and only had power where it was supposed to be and both grounds are good. I ohmed out the headlight assy and don't have any shorts.

I left the drivers plug disconnected and the motor will keep running when the hi beams are on, but kills when I reconnect it. Sounds like the problem is in that side, doesn't it?

It seems like it is backfeeding power thru that circut, but what I cannot figure out is why it kills when I pull the hi beam fuses.

FWIW, last summer I had the fuse block replaced because there was some corrosion in it that broke the fuel pump circut.

Does any of this help make any sense to this mess?
 

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2004 gmc
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Wish you had shared all that in the first post. You do indeed have some sort of backfeed issue, and it will take a good auto electrician to get at the bottom of it. Whatever corroded the fuse block last time wasn't stopped, and perhaps it came back. Or the corrosion, like unseen fungus, came back. The first thing I would do is pull out the fuse block again for a long and detailed inspection of all the connectors underneath and the wiring.
 

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Here was my cure :)

In my case a 1999 Chevy Astro Van. First it began having a hard time getting started and "up and running" ... then it began to immediately die when the high-beam headlights were turned on.
I dismantled, cleaned, and shot all ... and there are like 8 of them ... of the big ground commendations under the hood, then shot them with Caig DeOxIt contact restorer. A couple looked a bit suspect, and one on the firewall was corroded enough that it twisted off when trying to unscrew the nut. Each headlight had it's own ground to chassis connection ... and it would be easy to miss the one on the passenger side, behind the fluids reservoirs.
Fixed all problems ... she now runs great, even WITH the high-beams on :)
 

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Same issue exactly

Hey klarson2000, I ran across your post on this forum, I started having the exact same symptoms in October. The headlight on high beam kill the motor, then the left low beam head light is dim and the left turn signal flashes quickly all right side lights and turn signals work fine. If I turn the parking lights on the signals function properly. I have been driving only during the day, until last Thursday, had a birthday party and drove 45 miles at night with just the low beams on and I made it a block from my house and the motor started dying and the check gauges dash light came on and the rest of the warning lights flashed. I shut off the Trailblazer. Restarted it turned the parking light on and drove home the last block just fine. Did you even find out the cause of your problem?
 

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2007 chevy trailblazer_ls
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Hey klarson2000, ...
Since his last activity was over 7 years ago (10-20-2011 02:00 PM) he's probably not going to answer. And, as you can see by the dates on the 4 posts prior to yours, there is not a lot of response to resurrected old threads. You probably should start a new one.
 

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Same issue exactly

Hey klarson2000, I ran across your post on this forum, I started having the exact same symptoms in October. The headlight on high beam kill the motor, then the left low beam head light is dim and the left turn signal flashes quickly all right side lights and turn signals work fine. If I turn the parking lights on the signals function properly. I have been driving only during the day, until last Thursday, had a birthday party and drove 45 miles at night with just the low beams on and I made it a block from my house and the motor started dying and the check gauges dash light came on and the rest of the warning lights flashed. I shut off the Trailblazer. Restarted it turned the parking light on and drove home the last block just fine. Did you even find out the cause of your problem?
I'm having the same exact issue. Left turn signal flashes quickly when lights are on and dies with high beams. If I turn off the lights signals work fine. Has anyone solved this ?
 

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2004 chevy trailblazer_lt
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3,229 Posts
Well, the first thing you need to do is to check the grounds for all the headlights. There are multiple places where the lights are grounded. I would attach a circuit diagram for the headlight circuits and a picture of the engine ground locations, but I do not know what Year, Make, Model, Trim Level, and Engine you have. Please post that information. Also, please post any and all Diagnostic Trouble Codes (DTCs) are present when the OBDII system is read with a decent code reader/live data scanner.

Oh, and welcome to the forum!
 
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