I would like to know where the temp switch for the thermal fan

Ask Your Car Question. Car Experts Answer You ASAP.

(Not a Car Question?)

I would like to know where the temp switch for the thermal fan is located. My auto is a 1990 Mercedes Benz 190E 4 cylinder automatic. I donot have the 12 V for the magnetic coil after engine warm up. Appreciate the help. Thanks

Optional Information:
1990 Mercedes-Benz 190E 4 cyl

Already Tried:
metered magnatic coil with vom, tested good. Warmed engine up to approx 200 deg. fan did not energize. Dont have a manual at present so am lost as to where the temp switch is located.

Customer (name blocked for privacy)

Status: Closed Value: $15

Relist: I still need help.

ELECTRIC COOLING FAN DOES NOT OPERATE

TYPES OF FAILURES
Bad Fan Control Circuits - The fan control circuits fail to energize the cooling fan when necessary. This may be the fault of either the coolant temperature switch or the cooling fan relay.

Power/Ground Circuit - A blown fuse or broken/shorted wire is preventing the fan from operating. A poor ground connection may reduce the performance of the cooling fan.

Bad Fan Motor - The fan motor fails to operate when both power and ground are applied. If this is suspected, always verify that an object has not become wedged between the fan blades and shroud, and is preventing the fan from rotating.

CAUTION: When checking the fan blades for free travel and spin, always disconnect the negative battery terminal to prevent personal injury.

SYMPTOMS

< border="0" cellspacing="10" cellpadding="1"><>< valign="top">- < valign="top">Engine overheats at idle or low driving speeds.<>< valign="top">- < valign="top">Engine does not overheat at cruising or highway speeds.

NOTE: With speeds in excess of 25 mph, sufficient air flow is forced across the radiator to cool the engine without the use of the cooling fan (under normal conditions without A/C operation).

< border="0" cellspacing="10" cellpadding="1"><>< valign="top">Start the engine, warm up the cooling system and verify that the thermostat opens properly.

NOTE: Low coolant level or a stuck thermostat may prevent the electric cooling fan from operating properly.

< border="0" cellspacing="10" cellpadding="1"><>< valign="top">- < valign="top">Continue to allow the engine to warm up, closely observing the cooling fan, engine temperature, and expansion tank. Check that the cooling fan energizes at the correct temperature.

CAUTION: Do not allow the engine to overheat. Turn off the engine before:

< border="0" cellspacing="10" cellpadding="1"><>< valign="top">- < valign="top">Exceeding the normal operating temperature.<>< valign="top">- < valign="top">Coolant expansion tank level exceeds the maximum.

QUICK CHECK OF COOLING FAN CIRCUIT

< border="0" cellspacing="10" cellpadding="1"><>< valign="top">- < valign="top">Inspect:<>< valign="top">- < valign="top">Cooling fan fuse.<>< valign="top">- < valign="top">Cooling fan temperature switch and relay connections.<>< valign="top">- < valign="top">Associated wiring.< border="0" cellspacing="10" cellpadding="1"><>< valign="top">- < valign="top">Verify the fan blades turn freely and smoothly.

CAUTION: When checking the fan blades for free travel and spin, always disconnect the negative battery terminal to prevent personal injury.

I dont have a picture but it lists it to be in the top left hand side of the engine.Check the color coding of the wires to the sensors in water jackets in this area, it should be Brown white for one wire and green for the other..

Thank you for using Just Answer! Please ask for more detailed information.Please leave some positive feedback!
Accepts & bonuses are appreciated!

Reply to Gene's Post: Hi Gene, and thanks for the reply. I am not sure which sensor on the left side as explained. is the left side of the motor as you view from the front or from the inside looking out. There seems to be a sensor on the water pump that is connected to the temp gauge. The other sensor im not sure where it goes. your info is helpful and tells me i'm on the right track. I am trying to locate a wiring diagram but nada so far. Have located the relay for the fan. Any suggestions on how to check relay? Everything else checks fine.

The drivers side of the engine.Match the wiring colors as indicated. I am going to send the diagram to you in a private message as the file is too big to post in this answer thread.

Thank you for using Just Answer! Please ask for more detailed information.Please leave some positive feedback!
Accepts & bonuses are appreciated!

Reply to Gene's Post: Gene, Thankyou very much for your info. I am, awaiting the wiring diagram. Please rest assured that I will gladly contact you again in the future. Thankyou very much.

THIS ANSWER IS LOCKED!
You can view this answer by clicking here to Register or Login and paying $3.

Think you can answer this question?
Login or Become an Expert

DISCLAIMER: You acknowledge that any information you may obtain from individuals you contact through use of the JustAnswer service comes from those individuals, not from JustAnswer, and that JustAnswer is not in any way responsible for any of the information these third parties may supply. The site and services are provided "as is" with no warranty and no representations are made regarding the qualification of an Expert. Responses and comments on JustAnswer are for general information and are not intended to substitute for informed professional advice (such as medical, legal, investment or accounting) and do not establish a professional-client relationship. JustAnswer is not intended or designed to address EMERGENCY QUESTIONS which should be directed immediately by telephone or in-person to qualified professionals. Please carefully read the Terms of Service.

JustAnswer > Car Repair

I would like to know where the temp switch for the thermal ...

Related Answers