: 1978 Sedan DeVille EGR thermal switch?

08-15-13, 11:59 AM
My buddy's 78 Sedan has an EGR valve that stays slightly open at hot idle. We traced it back to the thermal switch under the distributor. Its leaking vacuum to the EGR valve. Its a 4 port switch. Two constant vacuum sources to it (front of carb and intake nipple) One to the vac. advance, and one to the EGR. All the listings show a three port switch to replace it. No big thing, just plug off one of the two constant sources. But could someone show me the order of hoses to this replacement switch? The three hoses to the one side of it are in a rubber manifold. The forth goes on the other side. Thanks for any assistance!!!

08-16-13, 01:47 PM

08-16-13, 02:36 PM
Hmmm, I wonder if the part was different for CA emissions or something? You really should try to get one with the 4 ports or see if the new one comes with instructions that would show what each of the 3 ports are for?