Chevy Silverado and GMC Sierra Forum banner

airbag impact sensor

1 reading
16K views 7 replies 3 participants last post by  EaOutlaw1969  
#1 ·
I have a 2008 Silverado. Some of the sensors are starting to go bad and I was trying to replace them. After watching a few videos on the impact sensors it seemed pretty straightforward so I ordered a set of new ones. Everything was as it seemed in the videos until I got to the 10MM bolts that hold the sensors. It took me two hours to get the driver side one unbolted. After wrenching on it a while, I finally came to the realization there was a nut on the top of the support that was spinning. I didn't see any mention of this in any videos. It was extremely difficult to get to and I eventually needed another pair of hands. The passenger side seems almost impossible to get to a nut on top of the support at all. That 10MM nut is immoveable now, it won't turn anymore at all.

What am I missing here? The truck is left outside all the time here in Ohio and was certainly rustier than the ones I saw in the videos. Any suggestions on the passenger side? When I go to put them back one, what type of nut do you recommend that will make it easier to get it to bolt down? Sorry for the new guy questions and I may just have done something wrong but I can tell you, my experience wasn't anything like the videos where they just unbolted.
 
#2 ·
Hi I can say after reading this it seems like you are elbow deep into this project. to help us catch up to where you are at it would be nice to watch the videos you watched. when you respond go to the full editor next to the submit button go to YouTube I guess is where you found the videos and copy the entire YouTube link on the full editor page click on the YouTube button and paste the link on the flashing cursor once posted the video you watched will show up for us all to watch.
Also what has brought you to the conclusion the sensors are bad? Just trying to get on the same page so any help that is offered will be useful to you.

Here is a link to a thread found on this site where they are discussing the same problem you are encountering Front airbag sensor replacement
 
#3 ·
One comment on many YouTube videos. The people that provide them usually live in a part of the country where a 12 year old vehicle isn't at all rusted so they make everything look easier that it will be if you live anywhere where metal rusts. I remember watching one video from Arizona where the guy was whining about how terrible a car was that he was working on that came from Ohio. He was pointing to "look at all of this rust!" and I thought "Gee, that car looks brand new to me."

I had to replace one of the sensors in my 2008 Silverado about 2 years ago. My truck also sits outside just East of Pittsburgh so I imagine that we have similar weather conditions on a 12 year old vehicle.

PB Blaster is your best friend. If you don't have any, buy a can or two.

Those 10 MM bolts screw into the bottom of the radiator support so they are in an area that gets abused constantly. Did you try to screw the bolt back in? In and out on rusted bolts will help when the threads are corroded. This is where the PB Blaster works. Open the hood, look around, try to find any visible view of the top of the sensor bolts. If not, lay on the ground and guess where the top of the bolt is. You will need to wear some PPE - glasses, a mask, a shield. You don't want this stuff in your eyes or your mouth. Spray the heck out of the area and then go and do anything else for about about 10 minutes. Hopefully, that will help you out.

Back to the question of replacing the sensors. If you don't know which sensor is causing the "service air bags" light to come on, I suggest replacing one sensor at a time to see if one of them makes the light go out.

You would also benefit from from Anti seize. Buy a tube. Put some on the threads of the new bolt before you screw it in. It will help if you or anyone else ever has to take those bolts out again.

Another product that I like to use is dielectric grease. Buy a tube of that and put a tiny amount on the end of the male electrical connection before you push it into the new sensor. This will help to keep moisture out of the connection.

Good luck.
 
#4 ·
I attempted to upload the videos but received a message that I was not allowed to.

Here are the links to the videos I watched:

I have an Autel Code reader which indicated both impact sensors were bad.

After thinking about this some more, I remembered that the shop I used replaced one of the sensors a few years back. After maneuvering the cooler in front of the radiator around a bit, I was finally able to see a nut for that sensor bolt. It is now just a square hole in the support. I am wondering if the shop put that nut on there when they replaced the sensor? I am going to need a nut that will not turn when I replace it as I can't get a wrench in there to hold it.

Unfortunately, I can't see anything on the passenger side and that bolt isn't moving anymore. I completely forgot about trying some PB Blaster. I am going to spray the heck out of it! I did try loosening it and tightening it to try and get it out but now it's stuck. After using the PB Blaster I will try to get something on the wrench to give me more leverage. I have both Anti sieze and dialectric grease. I'll use both.

Thank you for the replies. I am going out to spray it now and will let you know how it goes. Any suggestions on what nuts you would use ?
 
#5 ·
Well that depends on how much room you have on the bolt side. If you ever need to replace a captive frame nut in a boxed frame or other wise impossible to get to they make rivet nuts where you rivet the new nut in place but the tool universal multiple size tool generally requires a lot of room, they do make air powered rivet nut tools that require less room but they are costly and mainly used in the Automotive trade since. but leave it to a bored mechanic to come up with a cheap super close quarter rivet nut tool. ( i just found this one today on eBay ) I am not sure I would buy one from eBay but if you shop around I am sure you will find what works for you and your budget.

BTW if you know you are going to use the rivet nut tool like the one found on eBay you can disconnect the battery unplug the sensor and just cut the bolt off and fish out the nut and cut bolt with a cheap telescoping magnet. If the hole is too big for the rivet nut you will have to relocate the sensor by drilling a new hole or weld in the hole then re drill it out if you want exact OEM placement for the sensor.

BTW I feel your pain when it comes to rust when I worked in Fredericksburg VA as a Technician I remember the vehicle shaped rust rings I would have to sweep off the floor after replacing King Pins and other parts that required a lot of vibrations.

https://www.ebay.com/i/402333240750?chn ... gI4JvD_BwE

https://www.amazon.com/Astro-Pneumatic- ... ljaz10cnVl
 
#6 ·
Well, I got some leverage on it! After soaking it in the PB Blaster for an hour or so, it felt like it was turning again. I got it 3/4 of the way out, moving between tightening and loosening the bolt when it broke. I am thinking of pulling the radiator, drilling it out, and replacing the captive nut with some wing nuts. I would have enough room to get a screwdriver behind the wing nut when it turns to hold it if I ever have to do this again. I did find the nut that was used on the driver side, nothing unusual just a regular nut but it did replace the captive nut in the frame so the shop must have had trouble too.

I moved on to replacing the evap vent solenoid and, so far, it looks like that came out okay. I needed one win.

I'll get back to the impact sensors tomorrow. I am very grateful for everyone's' suggestions so far.
 
#7 ·
In case someone was curious about the result. I pulled the radiator and was able to work on the passenger side. I decided to cut the nut on the frame and just make it similar to the one on the driver side. I put a washer on the frame side that covered the hole and had my wife hold the nut still while I tightened the bolt from underneath. I decided if I still have this truck and it ever happens again, I will do the same thing if the bolt won't loosen.

The good news was that as soon as I started the truck, the airbag service message went away. I will check for the code later. I found my old bill and saw that the shop charged me $391.90 when they replaced the driver side sensor in 2017. Now I am moving on to replacing the TPMS sensors as the batteries are starting to go. I got a quote so far of $240.00.

When I was a kid I worked in a service station and in those days they actually did a lot of work on cars. The owner used to joke that "If we don't fix it, we'll screw it up so nobody else can!"

Thanks for all the help. I'm sure I'll be asking more questions.