my hvac vacuum solenoid alternative
Posted: Tue Jul 23, 2024 11:36 am
Found out a couple weeks ago that all 5 of my vacuum solenoids were leaking when energized. Since hvac vacuum solenoids aren't available new anymore and used ones are $50 each and with an unknown lifespan left I decided to look around for something else that would work.
Stumbled across this mercedes vacuum solenoid block that looked promising so figured I'd give it a shot.
Found a wiring diagram from a video testing one of these. They're solenoids so they work just fine with a common ground and switched power to the pin for each solenoid like the 928 uses.
Used mercedes parts on ebay frequently come with the electrical connector, but since I didn't want to mess with another used part I didn't get a connector (maybe that's able to be obtained separately?). So for now I used bullet style connectors onto the pins of the mercedes valve and adapted to the spade terminals that the factory solenoids use. Just left the caps on the two unused ports.
It tucks in there nicely for the most part. I still need to make a bracket or something so the other side can srew in too, but for now it's not flopping around or anything. All the actuators work as expected now and I could visually tell that my recirc flap switches fully to recirc now whereas before it didn't have strong enough vacuum to completely move.
Needs some polishing, but I think this has promise to be a good substitute for the NLA original solenoids.
Stumbled across this mercedes vacuum solenoid block that looked promising so figured I'd give it a shot.
Found a wiring diagram from a video testing one of these. They're solenoids so they work just fine with a common ground and switched power to the pin for each solenoid like the 928 uses.
Used mercedes parts on ebay frequently come with the electrical connector, but since I didn't want to mess with another used part I didn't get a connector (maybe that's able to be obtained separately?). So for now I used bullet style connectors onto the pins of the mercedes valve and adapted to the spade terminals that the factory solenoids use. Just left the caps on the two unused ports.
It tucks in there nicely for the most part. I still need to make a bracket or something so the other side can srew in too, but for now it's not flopping around or anything. All the actuators work as expected now and I could visually tell that my recirc flap switches fully to recirc now whereas before it didn't have strong enough vacuum to completely move.
Needs some polishing, but I think this has promise to be a good substitute for the NLA original solenoids.