I have been meaning to ask this question for a while. It is probably stupid, but I should know the answer before I screw something up. There appear to be two temperature sensors on the driver's side of the engine block. One has a wire that goes to the pre-glow relay. The other has nothing on it. Why is there two?
I am not sure where the Sensor is but I have read on my 300D it the temp gets above a certain amount the Electric Cooling Fan in front of the Radiator goes on (it is also supposed to go on when the A/C us turned on).
I am not sure where the Sensor is but I have read on my 300D it the temp gets above a certain amount the Electric Cooling Fan in front of the Radiator goes on (it is also supposed to go on when the A/C us turned on).
OT but FYI, that sensor switch is screwed into the side of your 300D refrigerant receiver-drier/accumulator (located in a hole, just forward of the right front wheel well). When it senses refrigerant temp in excess of 140F, it switches on that electric fan in front of the condensor. Once the refrigerant cools down, the same switch turns off the fan. Don't know what the switch off temp is though, sorry.
One is for the coolant temperature gauge, one is for glow relay of the loop-style glow plugs (wired in series). The pencil-type glow plugs have the temperature sensor in the glow-plug relay. There should not be a second temperature sensor on a 1981 model.
Okay, I will investigate this a little further tomorrow, but the rearmost sensor has a plug that connects to a wire that runs into the glow-plug harness. My coolant temperature sensor works fine.
The front one (engine temp sensor)was used in the pre-glow system up to '80, in '81 they switched to an
ambient sensor within the relay.
The rear one (coolant temp sensor) ends up at your gauge, all year models.
I also wondered about this. This morning, I installed my new coolant temp. sender on the left-hand side of the engine, right at the thermostat housing, but that didn't fix my inaccurate temperature gauge that was reading 50 or 60 degrees C. Disconnecting or reconnecting the wire had no impact on the temp. gauge. The wire connected to this sensor is brown. Here's a shot:
I checked my electrical troubleshooting manual and it shows that the wire from the coolant temp. gauge should be green, so I went and explored some more. I found another sender on the right side of the block, right next to the glow plugs:
This one did the trick (but now the temp. reads almost 100 degrees C, pretty consistently). What's the other sender for?
First off, the first pic is on the right side of the engine. Left and right on a car is always taken
from the drivers perspective. I'm not pickin' on ya, just explaining to avoid confusion.
The sensor in question is for the blower motor, to delay the blower from running until the engine temp reaches 40C.
Why are you making fun of me???? Just kidding...thanks for clarifying. I actually debated which way to explain and decided on that since it was from my perspective. Noted and will use the proper orientation from now on.
So I haven't heard my fan come on...Should I check something then?
No - BLOWER MOTOR. It's the squirrel cage fan under the dash on the passenger side. The switch under discussion acts as an interlock, to preven (cold) air from being blown out of the interior vents until the coolant temperature increases enough to close the switch.
//greg//
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