1975 GMC Pickup Heater Switch

[Admin-mags]

On our 1975 GMC Pickup truck when we turn the engine on the heater blower blows all the time, and we can't find a way to switch it off. Can anyone help us? The lever on the heater works on high, medium and low, but won't switch off. Is there, or should there be a separate switch to turn off the blower?
Also for anyone trying the bleed the brakes after fitting a brake master cylinder. I couldn't get a pedal no matter how many times I bled the brakes. In the end I opened the back bleed nipple and the front bleed nipple and bled them both at the same time, and I got a brake pedal. Hope that may be of help to somebody.

[tucsonjwt]

Our squares have GM's "new flow thru ventilation." This means that the blower is always on at a very low speed to improve ventilation in the cab and possibly reduce the threat of carbon monoxide build up in the cab if you have an exhaust leak.

If you search the topic on this forum you will likely find some posts on how to install a shut off switch for the very low speed ventilation setting. I think it might even be possible to cut the wire for that setting entirely, but that presumes that the always on low setting is not the same as the regular low setting.

[cadillac_al]

I used to unplug my blower motor in the summer. If it rains I can plug it back in in 1 minute.