Hi.

Today all of a sudden there is no heat coming from the heater blower.
Engine temp is ok, top and bottom radiator hoses are hot after warm up, A/C works fine. Car runs perfect.

Any ideas?

 

The plumbing for the heater has a dedicated electric coolant pump. They often fail. It's a fair guess that yours is on the blink.

It's been quite some time since I owned an X300 so details regarding the pump have faded from memory. However there is plenty of archived advice and discussion, I'm sure

Cheers
DD

 

Pump brushes tend to wear out and can be replaced. Also high on the probability list: Thermostat stuck open. Heater matrix clogged - back flush it with water hose pressure. Less common - Water valve stuck. Plenty written and pictured here on it. Don't neglect the TSB's posted by Motorcarman.

 

I had a stuck water valve,hit it with a plastic crew driver handle really hard whilst running and if you get some hot air that’s the problem ,easy enough to change

 

I changed the brush's and reasembled the motor. I connected to my power probe to test run and nothing, the circuit breaker triped on the power probe, so I guess a dead short. I took it apart and there was a smell of burning and a little smoke. I removed the diode to test it and it looks like it is fried. Anybody know what type of diode this is, it has EJ4 on it, but could not find much on the Net regarding it.
I also got a dead short when I tested the pigtail.

Cheers

Ian