HVAC Switchover Valves
05-16-2024, 08:38 PM
#1
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190E
HVAC Switchover Valves
Hello All,
New member here, I recently purchased a 1990 190E 2.6 5 speed MT. The car is on overall good shape with a few minor issues.
The biggest was the HVAC system, which didn't work at all. I was surprised/disappointed to learn the entire system is vacuum operated.
Luckily, I found a leak topside on the supply line to the switchover valves. I also replaced the blower switch and all seems to be operating normally.
My question concerns the switchover valves. While preparing to reassemble the dash, I grabbed the switchover valves and they were very hot.
On the bottom of the two valve bodies there are rivets and that is where it was hot to the touch. Is this a normal condition?
Thanks
New member here, I recently purchased a 1990 190E 2.6 5 speed MT. The car is on overall good shape with a few minor issues.
The biggest was the HVAC system, which didn't work at all. I was surprised/disappointed to learn the entire system is vacuum operated.
Luckily, I found a leak topside on the supply line to the switchover valves. I also replaced the blower switch and all seems to be operating normally.
My question concerns the switchover valves. While preparing to reassemble the dash, I grabbed the switchover valves and they were very hot.
On the bottom of the two valve bodies there are rivets and that is where it was hot to the touch. Is this a normal condition?
Thanks
05-17-2024, 12:52 AM
#2
Super Member
Congratulations on the acquisition. We will have to see some obligatory photo's soon. I have a 89' and 88' , both 5 speed MT's. Currently restoring the second which is in decent 36 year old shape. Many parts to replace/fix, fortunately I have a shelf full of JY parts I collected over the years.
I have replaced my actuator pods on the '89 a few years back. When you say the "switchover valves" are you referring to the unit behind the glove box in the dash for a US car? I do not see a reason why it should be hot unless you have the heater on. It should not be self heating as it is just vacuum operated switches.
I have replaced my actuator pods on the '89 a few years back. When you say the "switchover valves" are you referring to the unit behind the glove box in the dash for a US car? I do not see a reason why it should be hot unless you have the heater on. It should not be self heating as it is just vacuum operated switches.
05-20-2024, 11:05 AM
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Hello dolucasi and thanks for the quick reply.
Yes on the switchover valve unit beside the glove box and under the vent. I see the two valve bodies distribute vacuum to to the actuator pods and are electrically actuated.
The only thing I can think of is the electrical side causing that much heat. Also, with the system operating I hear various valves clicking with no additional inputs on the control panel.
Yes on the switchover valve unit beside the glove box and under the vent. I see the two valve bodies distribute vacuum to to the actuator pods and are electrically actuated.
The only thing I can think of is the electrical side causing that much heat. Also, with the system operating I hear various valves clicking with no additional inputs on the control panel.
05-21-2024, 03:15 AM
#4
Super Member
It's been a while since I took my dash out and replaced it. I do not recall electrical valves, but perhaps I have forgotten.
If they are constantly switching that seems like there is probably something wrong with the controller. I do not believe the box is supposed to get hot.
If they are constantly switching that seems like there is probably something wrong with the controller. I do not believe the box is supposed to get hot.
