No heat/defrost

[lmorgan]

I have an '04 w/ just under 200K on it. I've done an egr delete and replaced the oil cooler. I have no heat or defrost, regardless of idle or speed. I'm in the deep south, so our temps rarely get extremely cold, but when there's frost on the windshield, it's a safety issue. I'm not losing coolant that I can see and the controls and vents are working correctly. I don't have any gauges to go on re: actual operating temp except the dummy gauge inside. It seems normal to low. I normally use Ford gold coolant. I did flush it with distilled water and have been running that the last few days. The heater issue started last winter when it was full of Ford gold.

Any suggestions?

[portcity_gt]

I would check the vacuum actuated valve on the line going to the heater core, it's under the hood not the dash. Make sure the electric vacuum pump is working and there are no holes in the lines.

[lmorgan]

I checked the vacuum line and it seems to be in order. Or at least I think it's the correct line. This one is a small line that connects to a small round valve type apparatus on the heater hose. Is there another one that I'm not seeing?

I drove the truck last night for three hours. It took almost 45 minutes (according to the dummy gauge) to get almost up to normal temp, but the heater/defrost blew cold the entire trip, regardless of rpm, idle or speed. No heat at all, period.

What should I check next? I've read on here that it could be a thermostat or the water pump or a clogged heater core. I read somewhere else that it may be the blender switch under the dash.

Any suggestions?