Symptoms:
Upon fire-up the heater will sometimes but not every time have a rattling noise initially. It will then heat as normal up until the mid 80 degrees and then heating stops, I get a service heater light for about a minute then it goes out, heating light begins to flash then goes solid and the heater re-ignites. Heater will run a few minutes then the it becomes a continuous cycle of service heater light>re-ignite>service heater light. On and on. I opened it up and I am getting an HLS light when this happens.
Solutions I've tried:
Replaced thermal regulator (the thing that looks like a car thermostat)
Tested voltages on Thermistor, it checked out ok
Replaced HLS switch
Tore down manifold to check manifold bypass valve, it was intact.
Last ditch effort I ran heater without filters in place to check if it was a flow issue.
I'm stumped, what am I missing?
Upon fire-up the heater will sometimes but not every time have a rattling noise initially. It will then heat as normal up until the mid 80 degrees and then heating stops, I get a service heater light for about a minute then it goes out, heating light begins to flash then goes solid and the heater re-ignites. Heater will run a few minutes then the it becomes a continuous cycle of service heater light>re-ignite>service heater light. On and on. I opened it up and I am getting an HLS light when this happens.
Solutions I've tried:
Replaced thermal regulator (the thing that looks like a car thermostat)
Tested voltages on Thermistor, it checked out ok
Replaced HLS switch
Tore down manifold to check manifold bypass valve, it was intact.
Last ditch effort I ran heater without filters in place to check if it was a flow issue.
I'm stumped, what am I missing?
