Trailblazer Anomoly

dawgfan · January 9, 2003

Lately, my LTZ remotes have not triggered the unlock mechanism when the vehicle has been cold. It seems weather related. (Worked fine last winter.) I live in North Alabama, so it's not really that cold, but it's the only common denominator when trouble shooting this intermitent problem. Neither of the remotes will work sometimes and the batteries have been checked. Took it to a dealer today and NPF - the stupid thing worked flawlessly. Has anyone had this happen to them?

Shaners · January 10, 2003

I think the remote entry uses a "rolling code" like that of a garage door opener. I doubt that it could be the problem though, because the transmitter and recievers don't really automatically reset themselves with out special commands.

Since you say when the system goes down neither key fob works, so I would say the place to look would start with the reciever in the truck. I would think the reciever is going bad, or there is intermittant power loss to it for some reason. Most likely my best guess would be a bad reciever.

mcali17 · January 10, 2003

Does this problem always occurr at the same location, such as in your driveway? I had a friend that lived on a hill near a radio tower. Anytime I tried to unlock my truck at his house, nothing. Had to open it with the key. Turns out that there was too much interference from the tower, and it was disrupting the signal.

CMNTMXR81 · January 10, 2003

This is a problem with certain vehicles, specifically C/K Tahoe's and Suburban's. Never heard of it on an TrailBlazer though.

It has to do primarily where the transceiver (and it's antenna) is located within the vehicle. If it's in a place that is a little bit better insulated, say under the dash somewhere or even under a seat somewhere, it has a problem receiving the code from your FOB until you get real close. Conversely, if it's part of the BCM or placed close to a fender or in the rear quarter panel, you can work it from a mile away.

As previously mentioned, there could be other radio frequencies also interfering. Your transmitter (fob) sends out a really small amount of power, so if a lot of people in your neighborhood are talking on their cell or cordless phones, or you are next to a radio tower, range will also be effected.

dawgfan · January 13, 2003

Doesn't always happen in the same areas. It has to do with temperature I am convinced. Dealer checked batteries in both FOBs and cleaned them as well. As both remotes worked flawlessly for them, the problem could not be duplicated by the technicians. I checked both batteries when I got home and they meter out at just under 3V, so OK. My wife said the clock was "off" by about 3 hours one morning and that's about the time the remotes started screwing up. Based on some other responses, perhaps the 12V battery is the problem. Opinions?

CMNTMXR81 · January 13, 2003

Temperature certainly has an effect on it. When you took it to the dealer and they played with it, chances are, it was already in a nice 75 degree shop, the vehicle had just been ran, so everything was warmed up. The best way for you to prove it to them would be to let it sit their overnight and then go with the service writer/manager/etc and show him what you mean when you try it.

As to the trucks' battery being a problem, a 3 hr loss would mean something else is completely shutting off power at some point in time (which would be another problem). This would have no affect on the keyless entry system because if it works, that means the battery is powering it and therefore turned back on. The only thing I can think of otherwise is that the keyless entry system may be powered off the same circuit that powers the stereo/clock's memory power circuit.