defroster help!!!

[von guido]

I have a 78 and the defroster doesnt work. I have found a bad vacuum line and will replace it but the selector switch that has the vacuum line (bulkhead) for a lack of better terms looks fried. the copper inside has burn marks on it. I cannot find this thing to save my life!!! anyone had this issue or know where to find the part? I have tried all the parts stores.rock auto and lmc to no avail

[Rubble]

You might have to try a salvage yard,did you try a GM dealer? Might be one string on a dusty shelf someplace too..
Posted via Mobile Device

[tucsonjwt]

Have you read this thread yet?

http://67-72chevytrucks.com/vboard/s...roster+debacle

I have the new Delco parts shown in that thread (vacuum actuator and vacuum valve, but no switch), since I bought these parts and did not need them (I just needed to replace a cracked vacuum line.) PM me if you want to buy them.

If you need the switch you can get that at Classic Parts. If you need the whole heater control assembly you can get that at LMC.

Also, in my case, I also had a bad short harness which connected to the switch, which caused the defroster/A/C/heater to work intermittently. You can check that by pulling the heater control out of the dash and wiggling the connector on the end of the switch - if the defroster works intermittently then you probably have a bad harness. You can get the AC Delco OEM style harness with connnector online - one of the OEM vendors (oehq or oewarehouse, I forget which one) has an AC Delco catalog which allows you to search pigtails by the number of "cavities" in the connector, then scroll down to find the picture of the one that matches the one you need. Post back if you need some help on this.

Good luck.

[von guido]

i've called 3 gm dealers but probably have to go to a scrapyard..


I read the thread and the peice I am hunting is the vacuum valve but mine is shaped different with a 3 prong electrical connection on it.