Hvac Vacuum Actuators
#1
07-13-2018, 12:41 AM
Hvac Vacuum Actuators
Hello! I知 new to the forum (so please excuse if the question has been asked before, I did search but did not find anything on it). Does anyone know the part numbers or where to buy the three HVAC vacuum actuators for a 97 blazer? Two of mine are bad due to a failure of the transfer case switch and I may as well replace the third just in case, but I知 having trouble finding where I can buy them. Any help would be greatly appreciated. PS. Not looking for the electric blend door actuator, looking for the vacuum ones.
Last edited by LaFierte; 07-13-2018 at 12:44 AM. Reason: Mistake
#2
07-13-2018, 01:21 AM
Welcome to the forum. Sorry I don't know the part numbers for your 97. I do know about problems with the transfer case switch. Did transmission fluid get sucked into the actuators?
#3
07-13-2018, 07:29 AM
This place has only two of the three available, but they do give you the part numbers as well as drawings of all three parts
https://www.gmpartsgiant.com/parts-l...lectrical.html
https://www.gmpartsgiant.com/parts-l...lectrical.html
Last edited by LesMyer; 07-13-2018 at 08:02 AM.
#4
07-13-2018, 07:44 AM
here's the obsolete one on ebay
https://www.ebay.com/itm/New-Genuine....c100408.m2460
oops no longer available. You can google the part number and search that way to find someone who still has it as NOS, if the obsolete part is one of the two that you need.
https://www.ebay.com/itm/New-Genuine....c100408.m2460
oops no longer available. You can google the part number and search that way to find someone who still has it as NOS, if the obsolete part is one of the two that you need.
Last edited by LesMyer; 07-13-2018 at 07:59 AM.
#6
07-13-2018, 10:45 AM
When the input shaft seal on the transfer case fails it allows transmission fluid into the transfer case and overfills it until fluid gets sucked into the transfer case switch and throughout the vacuum system. Replacing the input shaft seal will solve the problem and keep the new actuators working.
#7
07-13-2018, 05:00 PM
Yep, already have corrected that end of the problem. I知 just working on correcting the problems under the dash now. Talk about a major pain in the butt... but to avoid future some problems I知 going to be running the HVAC actuators off a different vacuum port in hopes that if I ever have an issue again it won稚 flood the HVAC system. 
#8
07-14-2018, 06:05 AM
You and I have the exact same issue. My dash is currently out as well. I was only getting air out of the defrost and floor and so far I have been unable to find the root cause since I had replaced the vacuum lines under the hood and everything appeared to be in working order under the dash.
The blend door actuator had a bit of ATF, but still held vacuum. Heck, the actuator under the battery for the 4WD had about 3 tablespoons of ATF in it and still worked fine... A new t case switch and vacuum line between the source and t case are in order as well. I am also replacing the heater core and flushing the hard vacuum lines with Simple Green. I've been applying it daily for the last 4 days.
The lady and I are doing some junkyarding this morning in search of a 1997 2WD per a recommendation I received on another forum. Doesn't have to be a 1997, but from what I can tell it needs to be this dash/ front end style because the p/n's aren't the same with the 98+ models. Apparently the actuators are very reliable if they don't get contaminated with ATF from a faulty t case switch. A 2WD won't have the faulty t case switch!
Pain in the butt is an understatement btw. LOL!
The blend door actuator had a bit of ATF, but still held vacuum. Heck, the actuator under the battery for the 4WD had about 3 tablespoons of ATF in it and still worked fine... A new t case switch and vacuum line between the source and t case are in order as well. I am also replacing the heater core and flushing the hard vacuum lines with Simple Green. I've been applying it daily for the last 4 days.
The lady and I are doing some junkyarding this morning in search of a 1997 2WD per a recommendation I received on another forum. Doesn't have to be a 1997, but from what I can tell it needs to be this dash/ front end style because the p/n's aren't the same with the 98+ models. Apparently the actuators are very reliable if they don't get contaminated with ATF from a faulty t case switch. A 2WD won't have the faulty t case switch!
Pain in the butt is an understatement btw. LOL!
