Hot/Cold knob not moving

[MH77280Z]

Took another pic under the dash…these 2 hoses seems to be old and I do see slight dampness. Can these be replaced from in dash easily? I assume I had to drain the coolant?

[MH77280Z]

[Namerow]

Sorry.  I missed the '280' in your user name.  I'm not familiar with the 280 heater, so you'll have to rely on other members for help.  Having looked at your pictures, I suggest you start by putting some good-quality penetrating oil (not WD40) on any fastener that looks like it's going to need to be loosened.  If you do that now, it will same you a lot of grief when you actually set to work on repairing the system.

[Captain Obvious]

1 hour ago, MH77280Z said:

The silver thicker one goes to this orange module. What is this orange module?

That orange module is the temperature control switch for your A/C compressor.   The temp silder lever on the HVAC control panel does one of two things:

When you are in non-A/C mode, the temp lever controls the amount of water flowing through the water cokk. But when you are in A/C mode, the system automatically cuts off all water to the heater core using the vacuum controlled valve that lives near the water cokk. So when you're in A/C mode, no water flows through the core regardless of where the lever is. And then in that A/C mode, they instead use the slider lever to control the setpoint for that orange device.

That orange cube is a temperature controlled switch with a sensor stuck in the evaporator coil. If the evaporator warms up enough, they turn the compressor on. And if the evaporator cools off enough, they cut off power to the compressor.

Basically, they cycle the compressor and the duty cycle is dependent on the position of the temperature slider lever.

TMI?     

[MH77280Z]

57 minutes ago, Captain Obvious said:

That orange module is the temperature control switch for your A/C compressor.   The temp silder lever on the HVAC control panel does one of two things:

When you are in non-A/C mode, the temp lever controls the amount of water flowing through the water cokk. But when you are in A/C mode, the system automatically cuts off all water to the heater core using the vacuum controlled valve that lives near the water cokk. So when you're in A/C mode, no water flows through the core regardless of where the lever is. And then in that A/C mode, they instead use the slider lever to control the setpoint for that orange device.

That orange cube is a temperature controlled switch with a sensor stuck in the evaporator coil. If the evaporator warms up enough, they turn the compressor on. And if the evaporator cools off enough, they cut off power to the compressor.

Basically, they cycle the compressor and the duty cycle is dependent on the position of the temperature slider lever.

TMI?     

That explains it well. Appreciate

[MH77280Z]

What about the two hoses in the pic. I think changing those would need all coolant drain first correct?

[Captain Obvious]

3 minutes ago, MH77280Z said:

What about the two hoses in the pic. I think changing those would need all coolant drain first correct?

Yes, those hoses are full of coolant and will gush some when you take them off. With that in mind, I would drain the coolant first to minimize the mess. There will still be some coolant coming out of the tubes even after draining the system, but probably less than if you didn't drain the system first.

Oh... And when you're all done with the coolant leak repair, I would disconnect the electrical connectors that go to the center console and clean them out. It's common for those connectors to be green crusty corroded due to heater system leaks over the years getting inside the contacts and sitting wet and festering.

[Patcon]

Also, you will have better success with the hose clamps if you use an actual JIS screwdriver!

[Roberts280Z]

I had a similar problem.  I removed my water valve in order to free it up.  But then I eventually decided just to inhibit all the coolant flow into the cockpit by plugging the lines, rather than risk anymore leakage.  This is not a daily driver, and I'll never need a heater here in Houston.

[MH77280Z]

Getting back on this topic, with car at normal operating temp and vent on Heat and full hot my fan DO NOT blow hot air 🙂

Does that mean air it not getting to the heater core? door not working? or water **** jam? my level is freely moving from COLD to HOT and i do see movement at the watercock (external connector etc.)

Where to start? also do u think the two in cabin hoses can be serviced without taking the blower motor out?

[Zed Head]

Could be the vacuum cokc.  It controls coolant flow through the core.

 

[MH77280Z]

There is a vacuum **** and a water **** in the diagram they both have to function to allow water through the core I think? The water **** is a mechanical one and I believe does move with that thin wire I have been playing with. The vacuum clock is located at the same place? Dumb q but I will look at the manual more closely.