89's SC five speed. New reman motor from ATK installed. New temp sensor, water pump hoses and so on. Fan works high and low with direct power, but not when plugged into the IRCM. Check continuity from the IRCM to the fan - good. Replaced IRCM - no fan. I unplugged the ECT - fan comes on. I believe the ECT is original, but I checked the resistance and it seemed ok. 16.4 K ohms cold. 3.4K ohms when temp is on "O". Please let me know where to go from here. Thanks everyone.
Cooling Fan - everybody loves this subject
- Thread starter Barkman42
- Start date
TbirdSCFan
Registered User
Hmmmm... coolant level full? Since the ECT sits at the very top of the circuit, if the coolant is slighty low, it won't get the right reading and may not trip the fan.
Takes effort to set up, but I've recently taken to measuring volts at the ECT, not just ohms.
I found that when things are working normally, the low speed fan comes on at 0.37v coming out of the ECT, at it's connector.
Before getting to that point, tho, I like to verify these components: EEC, IRCM, fan motor and it's connector, by connecting a code tester and doing a KOEO/ER test.
As we've discussed in the past, this test will attempt to run the fan at both speeds, low then high, one right after the other. If you initiate a test while standing at the pass. side fender, near the fan, you should be able to hear it start and step up low/high very quickly. If this testing doesn't show that, then you need to stop and find out why. If all is well, then volts test at the ECT. You'll need to patch inline with test leads between the ECT and it's connector. Helps to watch the temp gauge in the dash and note the volts reading live vs. where the needle sits as the car heats up, so you have a general reference going ahead. Begin with a cold engine, if possible.
This testing assumes no codes, good thermostat, radiator, radiator cap, water pump, coolant concentration, belts, heads/gaskets, etc. etc. and just focuses on the electrical components. Use your notes to report back on readings at the ECT, but...if it is indeed the original, I'd not be shy about purchasing a new one. AutoZone sells one with a lifetime warranty, BTW
I found that when things are working normally, the low speed fan comes on at 0.37v coming out of the ECT, at it's connector.
Before getting to that point, tho, I like to verify these components: EEC, IRCM, fan motor and it's connector, by connecting a code tester and doing a KOEO/ER test.
As we've discussed in the past, this test will attempt to run the fan at both speeds, low then high, one right after the other. If you initiate a test while standing at the pass. side fender, near the fan, you should be able to hear it start and step up low/high very quickly. If this testing doesn't show that, then you need to stop and find out why. If all is well, then volts test at the ECT. You'll need to patch inline with test leads between the ECT and it's connector. Helps to watch the temp gauge in the dash and note the volts reading live vs. where the needle sits as the car heats up, so you have a general reference going ahead. Begin with a cold engine, if possible.
This testing assumes no codes, good thermostat, radiator, radiator cap, water pump, coolant concentration, belts, heads/gaskets, etc. etc. and just focuses on the electrical components. Use your notes to report back on readings at the ECT, but...if it is indeed the original, I'd not be shy about purchasing a new one. AutoZone sells one with a lifetime warranty, BTW
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- the dealer might refuse to work on one of these cars.
You might want to save yourself a trip and discuss it over the phone. Maybe you'll get lucky, tho, and find one with someone on staff that knows about them.
Good luck
Rotaryeccentric
Registered User
I began using one of these on my '94 over 7 years ago. And my SC was my daily up to last September.
http://www.dccontrol.com/constant_temperature_controllers.htm
Very pricey for fan control, and it took 3 months to be delivered, but it has been consistent on controlling the fan. And even an idiot like me figured out how to put it in the car.
Just an idea for fan cooling, sorry this is not that well related to your EEC/ ETC troubleshooting, but thought it may give you an option.
http://www.dccontrol.com/constant_temperature_controllers.htm
Very pricey for fan control, and it took 3 months to be delivered, but it has been consistent on controlling the fan. And even an idiot like me figured out how to put it in the car.
Just an idea for fan cooling, sorry this is not that well related to your EEC/ ETC troubleshooting, but thought it may give you an option.