Cruise Control

[kcdano2017]

Hey all,

Sorry to post this but I am in need of some help. So my cruise use to work no issues but after having my brakes converted to hydra boost it stopped, what is strange is the switch works and when I push the button the light on dash turns green like it is set but will not hold speed. Just trying to trouble shoot. I normally would have my mechanic look at it but he is 2 mo out. Thank you for any help. Also wondering is it possible that this and my A/C stopped working be related?

 

[pacecarta]

theres a 3port check valve behind driver valve cover at firewall
that valve holds the vac in the lines for the HVAC doors and the cruise servo ,
from that valve theres a rubber vac line that runs along firewall and driver fender and splits at a Y to the cruise unit and then into the fender under the plastic wheelhouse to a vac reservoir ball
the check valve can go bad and not hold vacuum but you will have vac at idle that goes down when accelerating
any cracks or splits in the vac lines will cause a no vac situation and the cruise servo cant operate , also the hvac doors cant be operated and the vent doors which are vacuum operated dont work and air is directed to the floor

theres also black plastic vac lines from the 3port check valve and heater valve that run along the ac box and they get hard and break from engine heat

no ac could also be low refrigerant charge preventing compressor engagement
no cruise after a hydro conversion could also be the cruise vacuum switch under dash isnt contacting the brake pedal arm