97 Olds 88 with heater relay chatter

I own a 97 Delta 88 with 120 k on it. runs and starts great. Lately, I have a howling noise from under the hood. I thought it was the heater motor but when switched to the Low or Off position, sometimes the howling is still there. My wife even smells a burning smell but I haven't been able to locate it. I checked the resistor pack and its good. I am starting to wonder if it could be one of the Omron relays that is starting to chatter but i never experienced one failing before. Has anyone run into this situation before or can someone comeup with a good suggestion. Your help is appreciated.

P.S. I need the heater. ITs been -25 for the last week with windchill making -39.

Thanks.

Seems to be a little confusion here.........never heard of a relay that caused a howling noise......and when you shut the blower off, the noise is still there.....is this noise present when the vehcile is stopped or only when in motion?

Do you have all blower speeds? Does the temp control work ok?

Your coolant level is ok?

Burning smell could also be the valve covers leaking on the exhaust.....

Some relays before dieing will start to chatter wildly, (this is from experience working as an electrical tech for a utility, usually a failed coil in a relay). Coolant level okay, valve covers not leaking as I had the manifold gasket replaced last fall. Of the 4 blower speeds, I have low and high. The next one past low stays on low and the one before high is a dead spot. The problem was intermittent before, but i was able to maintain it this morning. Even with engine off, but key turned to have ignition "On", noise still there so that eliminates the compressor. Placed hand on heater blower and felt huge vibration from there, so now I am convinced that it could be the heater motor and not a relay.

I think I might have found the problem. But seeing how you took the find to reply, I will answer your questions in the event that i didn't solve my issue.
The noise was intermittent until i got to work this morning. Now the noise is almost on all the time. As long as the heater motor is on, even with the engine off, it still howls, so to me that should eliminate the A/C compressor.
Whether the selector switch is in defrost or be-level, the noise still there. It just seem to disappear before when selecting between the two.
lifted hood while noise was there and felt huge vibration in heater motor which is probably blown bearings.
As for the coolant, level is good.
No apparent leaks on the exhaust as I has manifold gaskt replaced in fall.
Only time noise disappears is if selector switch is in the OFF position. That should cut power to blower.
As for blower speeds, out of 4 speeds, I have low and high. Next step after low is still low and the one before high is a dead spot. Not sure if I have issues with the spped switch. Checked resistor pack for speed and they are good. Had a spare and no difference.

My guess now is the heater blower motor. I am going to take it out after work and hope for the best.