Well I have ripped my whole dash apart to do a blue led conversion, also I have to do a pitman arm and idle arm change so I can finally get it allaigned after my lift kit. Well I had already ripped my dash apart when the blazer was on the side of my house in the rocks. So for the pitman, and idle arm change I wanted to move the truck to the drive way. So without a guage cluster and the rest of the dash I started her up and moved her to the drive way. After changing the guage cluster lights I went and plug it back into the car to see if they worked since the are polarized (had to make sure positve and negative were in the right spot) Well for some reason my battery was dead. So I jumped it. Tried to start her up but as soon as she started she died. If I held the gas in and started her up she would run but soon as I let off she would go to idle then die. So I spent most of my day yesturday checking the forum for possible problems. EGV or bad fuel pump pressure were some of what I could find.But I started thinking this morning. The only thing different I did after I moved her to the driveway was take out the HVAC to do the conversion to it. So I plugged it back in, starter her up and she ran fine. For some reason I'm not understanding what the HVAC has to do with the engine idleing. She's back to normal now but its buggin me and would like to know what it has to do with it in idle? Does it have to do with some kind of vacum? I'm really stumped. Any closer on this would help me sleep tonight. THX.

 

I think its the LEDS

I dont know why, but as soon as I put them in, my whole truck was dead...wouldnt start, ran wierd...

took them out and eveyrthing is fine again.


A guy at work who use to work at a dealership, told me that theres a certain voltage needed for the sercuirty program on the blazer and adding additional items, (ones that are not connected directly to the battery) like loose LEDS will cause your truck to run differently. I spliced mine into the headlights, so they would turn on with the headlights and nothing but problems came after that.

Some other users have done this succesfully, maybe I did it wrong, but thats my .02cents.

 

Vacuum it is. A LOT has to do with vacuum on these trucks, and I'm assuming a lot of newer vehicles as well.

EDIT: Is that what caused it to idle funny? Possibly. But positively vacuum effects a lot.

 

On some of the newer modles some of the important electrical wiring runs through all sorts of different controls like on some models certain things run through the factory head unit!!

 

I have never heard of the s-series trucks having this type of problem. I know that quite a few newer vehicles are like this (my Rainier), but never heard of it being a factor in the s-series.

Are you sure that you have plugged everything back in and didn't damage any of the wiring in the process? There are others here that have messed with these bulbs without this problem... But it does sound like the security system is going nuts for some reason...

 

I've unplugged everything. Guage cluster, 4wd selector, rear window wiper/hatch, radio, driver and passneger window controls, and the HVAC panel. The only thing I plugged back in was my guague cluster to check the lights and thats when i had the start but instintly die problem. I left the guage cluster plugged in and pluged in the HVAC panel back in and then boom.. truck runs fine again.

What do you mean the security system seems to be going nuts?

 

Sounded like the factory security system was shutting the truck off for one reason or another.

 

Wierd, never had anyproblem like that in my truck when I was doing the conversion to LED's. The only thing was if I didn't have the 4x4 switch in and on 2wd, once I removed it, it automatically locked it into 4x4 hi, which was weird to find out when I was driving somewhere. I drove around with the dash apart (always had the guage cluster and 4x4 and radio in and had no problems, didn't always have the HVAC controls so I have no idea why your blazer is acting the way it is. How are you hooking the LED's up I might be able to tell if you are doing it way different then me. Sounds like I would keep the HVAC controls and cluster plugged in if you got to drive it. Good luck and keep us posted.

 

Some wierd fluke must have happened then. I'll put up a pic tomorrow of how I did the LEDs for the HVAC.

 

I do believe that the dial that controls your HVAC function (def, vent ,heat ,panel, floor etc) is vacuum controlled. If you had that off it may be a big enough vacuum leak to stall you at idle. When I had mine off my engine would surge to high idle , almost stall then back to high idle repeat. It had me scratching my head for a while then I heard the leak, plugged it ,then it idled down to normal.