As the title says all my heat and ac are going to defrost. My vacuum lines are all connected and I have vacuum at the pump, at the 90 on the fire wall and at the 90 that turns into the firewall to the hvac. I do not have vacuum at the switch. I cannot seem to find a pin out, for lack of a better term, for the connection to the controls. I am assuming the black tube is the one supplying vacuum to the controls. Not sure that matters since I can feel no vacuum at any point on the connector. I am seriously thing of capping the line at the passenger side firewall and just bringing a new one thru the driverside straight to the connector. Does any one know if that supply line connects anywhere else before it goes to the controls? Or does any one have a map of the HVAC vacuum lines?

12 hours ago, Mopar1973Man said:

 

What are you asking me to tear out my vacuum system and replace it with all air brake line and upgrade? 

Well that and maybe reroute it some, sounds like you mentioned out bodies were modified from gassers to diesel and may be some short cuts can be had. Then of course a simple version of how to do it 

1 hour ago, Dieselfuture said:

Well that and maybe reroute it some, sounds like you mentioned out bodies were modified from gassers to diesel and may be some short cuts can be had. Then of course a simple version of how to do it 

On 4/12/2019 at 1:57 PM, dripley said:

I have had that seepage seems like since new.

Some ac manufacturers have up to 5% bypass air built into the system.

15 hours ago, IBMobile said:

Some ac manufacturers have up to 5% bypass air built into the system.

Mine was more than 5%, just by feel anyway,  more 15 to 20. But going straight to the selctor stopped it. It seems to have moved it to the floor. But I dont know that for sure because I dont think I ever paid any attention to it.

 

On a different note about 3 months ago put the truck into 4wd and the light did not come on. It did not seem to be in 4wd but at the time I ignored it figuring to deal with it later. Thought about it again after replumbing the the vacuum line. So I put it in 4wd low and still no light. Even backed it up and down the drive way, nothing. So I put in 2wd hi and backed out of the driveway. When I made the right hand cut onto the road you could feel it bind up. Sure enough I had it in 4wd hi. Put in 2wd hi and it backed out fine. Burnt out bulb maybe or more vac leaks???

More than likely switch or corroded wire on a switch itself on the vacuum actuator, but I suppose if you had week vacuum It could have pulled it halfway in enough to engage the collar to have 4 by 4 and not enough to trigger the light

 

Could be the diaphragm is going bad also in the actuator, Mine rotted away that's when I put posi lock in

Edited April 15, 20195 yr by Dieselfuture

3 hours ago, Dieselfuture said:

More than likely switch or corroded wire on a switch itself on the vacuum actuator, but I suppose if you had week vacuum It could have pulled it halfway in enough to engage the collar to have 4 by 4 and not enough to trigger the light

 

Could be the diaphragm is going bad also in the actuator, Mine rotted away that's when I put posi lock in

Have to dig into it a bit more in the weeks to come,