2007 chevy trailblazer remote start issue

My wife recently had a local (reputable) shop install an Autostart as-1774sr in her trailblazer. Since day one it has had some issues. If you let it sit for 4 hours plus, the remote start will not start the vehicle. If you go and start and stop it with the key, it will then start with the rs as many times as you like.

Last night I started it probably 15-20 times in a 3 hour period without any problem, except the radio stayed on for over an hour at one point, but I'd guess that was due to me starting and stopping it so many times. I was able to clear that with a cycle of the key. I did a visual of the wiring,it is a tidy install. I didn't mess with their work and risk screwing up any warranty I might have. I also checked to make sure that power was dropping from the accessory wires when starting with the key and the rs, it was.

Today, while doing some informal testing, she found that it would only start the truck as long as the heater fan was shut off completely.

We have had it back to the shop twice and it is going back again this week. They have been great with service, they reprogrammed the bypass, then replaced it and the brain of the rs, but the issue remains.

I just thought that maybe some of the guys here might have run into this before. At first I was thinking that maybe the gem/bcm was going to sleep and the rs wasn't waking it, but when it does try to start the truck, you can hear the locks engage, the park lights come on and the fuel pump runs, even the wipers work. I tries to start the standard 3 times then shuts down.

I used to be an automotive tech, but have been out of the trade for a few years, I wasn't comfortable installing it for her. I have done many alarms and remote starts, but that was back before the new bypasses....like back in the key-in-the-box bypass days...lol.

Any input would be greatly appreciated

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Hey, is this supposed to spark like that?

If not cranking at all with the remote start, but always starts with the key it safe to say statistically you have some sort of remote start issue for sure. Given the issue as you have described, I would take a long hard look at the bypass module being used on that truck. It sounds almost as if when the truck has sat for a few hours and the system is then engaged that somehow it can't properly replicate the passlock value needed to disarm the passlock system. The other possibility could be, as the voltage drops while the car is at idle that it just can't generate enough power to crank the starter. The second I would say is not very likely though. Another thing you should know, having owned a Trailblazer myself is that they aren't exactly the most stable of platforms electronically. For the most part, 8 of 10 will work without incident but the other two will to a number of weird things. If that truck came into my shop, I would start with switching to a different bypass. Having a day or two to test thoroughly is generally nice too because it will allow for assurance that the issue has been solved rather than making an educated guess.

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there can be only one.......

Thanks, yes we have discovered the wealth of info found on the trailblazer forums. The troublesome ignition switch, buzzing stereo, lackluster bose in-dash changer, fragile transfer cases, and wonky lift gate buttons. None of this shocks me, as my mother has had 2 malibus, and I had 2 gmc trucks that were plagued with electrical problems. I've bought nothing but Ford for the last 10 years because of my last gm product, but the wife fell in love with this TB so she bought it.

Again, the shop has been awesome in attempting to find the issue, I just figured that I would look for a solution too.

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Hey, is this supposed to spark like that?

Here is a link to the video I took of it trying to start, for the guys at the shop.

https://youtu.be/3uGn4x9LNEQ

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Hey, is this supposed to spark like that?

I would say you need to check 2 things. First would be the passlock light on the dash. it should light up solid and then go out. if its flashing while its trying to star then I would say its a bypass problem. Basically look at what the light does with the key when starting, then look through the window when remote starting and see if the light acts the same.My description of what the light is supposed to do may be off a little, that why you should look at what it actually does with the key first.
second, I remember something with the trailblazers and their alternators. I think that they don't kick in for a few minutes. As a result, when an installer doesn't connect to a tach wire, that can cause a no start condition also. Make sure that your installer is connecting the tach(white wire). Its right under the dash in the large loom that goes from left to right. They might have grabbed the brake and parking light wire from that very loom. There are 3 or 4 white wires in there. they have to make sure they test the wire for tach. if it is connected and he got the tach wire from there, maybe he grabbed the wrong wire. They can also grab it from behind the cluster. its the only white at the cluster.

We ave found for certain that it will not start if the fan is in any position but off. As soon as it is turned off, it will start every time..... *scratches head*

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Hey, is this supposed to spark like that?

Did you have the battery tested ? Maybe the system is set to sense voltage instead of tach and when the fan is on it drops the voltage too low. I had one do this recently changed to tach sense and replaced the failing car battery.

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If i Can't Install it    I Don't need it   Joe

Thanks for the replies folks. Here is an update on this situation.

According to the shop, the sensing is done thought the bypass module (via data, I assume). The charging system is good, I replaced the battery and alternator less than 6 months ago. These vehicles are known to have problematic ignition switches and instrument clusters..... Is there any chance that might be the issue? The battery light is illuminated very faintly, the dealer said it could be the switch or the $450 cluster, plus programming. I'm going to try the switch, since it is only $50. The shop has given up and offered to remove the system and refund the cost. I understand they are frustrated and can't spend any more time on it. But the odd thing is, it will work perfectly if the fan is off, or on the lowest setting, anything higher and it won't start. I'm thinking temperature control module, or ignition switch. I just can't see anywhere in the vehicle wiring diagrams where the cluster is tied into the heating system, so I don't feel that it is related to the intermittent starting.

Ideas?

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Hey, is this supposed to spark like that?

alstaregixxer wrote:

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According to the shop, the sensing is done thought the bypass module (via data, I assume).

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The bypass module reads information from the databus in the vehicle, then converts that signal to AC for your remote start. I have not had much luck with data tach in GM vehicles. I would suggest to the shop to run the tach wire to the white under the dash (it's in the same harness as parking lights). Very easy to get to, and the most reliable tach connection available.

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Installer, IT support, and FFL. I need less hobbies.

Twelvoltz is right that at least one bypass manufacturer has had some tach issues with GM trucks.

I've had a run of a few Trailblazers this season already, and on all of them, there's a wire harness that runs horizontally along the bottom of the dash---I get parking lights, brake, and tach all there.

I did just think of one other thing that could be an issue on the 2006+ Trailblazer.

1: When you activate the remote starter, and then the ignition turns on (you'll see the dash warning lights all come on together), does the starter motor crank immediately, or is there a small delay?

2: Leave the windshield wipers in the on position, and activate the remote starter. Do the wipers stay on during remote start?

The reason I ask all that is because the Trailblazer has the following under the dash coming from the ignition switch:
---Two constant power wires
---Two ignition wires; they show power in the Run and Start positions
---One accessory wire (orange) that shows power in the Run position only
---Another accessory wire (brown) that shows power in the Accessory and Run positions
---A starter (yellow) wire that shows power in the Start position

On nearly every GM car on the market, the brown wire can be left unpowered during remote start. I actually prefer it this way, as the brown wire powers up the wipers and sometimes the radio. By leaving it unpowered, the wipers are disabled during remote start, and on some models, the radio stays quiet too---no need to wake up the neighbors every morning with the radio.

However, on the 2006+ Trailblazer, if the brown wire is left unpowered, the starter motor will crank immediately as soon as the ignition circuits (pink and white) come on.

This will work well enough if the engine was just running....I'm guessing because it's still warm, still has residual pressure in the fuel lines, et cetera.

So basically, if the installer doesn't power the brown wire, the remote starter will start the car super fast, but it'll still work, and the installer will shrug his shoulders and call it done.

Inevitably, after the customer has the car at home for a few days or so and it gets cold enough, it often won't work reliably. Sometimes it'll still start on the second try, but not always.

So basically, see if the wipers come on during remote start, and if they don't, have the shop power up the brown wire during remote start.

P.S. I wouldn't replace your ignition switch. A properly installed remote starter essentially IS a remote-controlled ignition switch.

Therefore, even if the ignition switch were bad, the remote starter would still power up all the circuits during its runtime....the car would run perfectly, at least until you do key takeover and press the brake.

I've seen these ignition switches go bad where one or more of the circuits isn't powered up until the switch is replaced.

I think you can pretty much do your own ignition switch test, without taking the car apart.

White ignition 2 wire: Rotate the key just a hair forward from Off; this should make the battery light come on, I'm pretty sure.

Brown Accessory wire: This powers the wipers; do they work?

Orange Accessory wire: This powers the climate controls, you did say they worked.

Pink Ignition 1 wire: Powers fuel/ignition stuff; car wouldn't run without this

Yellow starter wire: If you're a tech I'm sure you know, but the engine would never start without this

Thanks the reply, I'm going to try and touch on some of the points you mention...

1- When it works, the dash lights all come on, you can hear the fuel pump run and then 2-3 seconds later it will crank. When it doesn't work, the lights come on, but no fuel pump. The remote start seems to go through its 3 attempts, but with no crank. I have sat in the truck and tried to remote start it with the fan on high, then after the first attempt, turned the fan off, the truck started on the 2nd attempt.

2- The wipers and radio do work when the remote start starts the truck.

3- I'm thinking that the harness you mention is the one with the white label "fap fap fap" on it.

4- replacing the ignition switch was an attempt to shut off the dimly lit battery light in the cluster, no so much for the remote start.(But would have been a bonus if it fixed the RS too, lol)

5- the only thing I'm not sure of is the tach connection. Because I didn't want to mess with their install (untape and see what is connected where) and void any install warranty, but at this point, they want to remove the system and refund the money, so there is no concern on my end about the warranty.

I feel I need to state that I'm not unhappy with the shop, they have tried to fix it 4 times now. Being from the trade, I know that you can't afford to spend huge amounts of time on a car, and the remove and refund is the best way for them to get away from it. However, this still leaves me with no remote start. That is why I'm trying to problem solve it myself. I talked to Directed Tech Support today and they suggested taking it to another dealer to see if a fresh set of eyes could help.

Thanks again for the replies, I'm not a huge contributor to this forum, I contribute on other, more repair based forums. It is nice to know that there are people willing to take time out when they can to reply.


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Hey, is this supposed to spark like that?

Try turning engine checking off or go to voltage just for grins since u can't over crank, since you mentioned it doesn't start that's leads me to believe its a pass lock issue or the physical unit itself

See if it's wired d2d, the base model DEI stuff has issues with d2d and w2w is always the best option on them. drop the dash and see what the bypass led is doing when the vehicle dosen't start. Did they use a relay to trigger the 2nd accessory and 2nd ignition wires or just jump the wires together? What bypass was even used? Might be worth resetting and reprogramming the module as well.

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Thanks again for the replies. It'll have to wait a few more days. It is currently -22C outside and we're expecting 15cm of snow tomorrow. (I do snow removal)


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Hey, is this supposed to spark like that?