Wiring for Cooling Fan (Page 1/1) altownsend JAN 19, 01:41 AM 1986 Fiero 4-speed The cooling fan does not come on. I tested it (two wires - one is power, the other is ground), and the fan works as expected. I pulled and grounded the one wire from the Coolant Temperature Sensor (green with white stripe). It does not turn the cooling fan on. The fan relay has four (4) wires on the connector (red-hot, black-ground, two brown (I think). I presume one is high speed, the other low speed. I need some assistance with troubleshooting my problem and learning a solution to get the low speed working based on the water temperature. I want to get the A/C high speed hooked up also. The A/C is not working either. For now, I want to get the water temperature sensor to turn the fan on. Thanks to the person who has and shares the fix with me. Patrick JAN 19, 04:40 AM quote Originally posted by altownsend: I pulled and grounded the one wire from the Coolant Temperature Sensor (green with white stripe). It does not turn the cooling fan on. Are you referring to the Fan Switch? olejoedad JAN 19, 07:54 AM The 86 has a single speed fan. altownsend JAN 19, 05:12 PM Yes, the fan switch is what I was using to see if the fan was working, and of course, I grounded the GRN/Wht wire to see if the fan would operate. The fan did not operate. Today, Sunday, January 19, I purchased the ECM and Temp switches along with the fan relay. I will install tonight to see if the fan works as designed. Patrick JAN 19, 05:59 PM quote Originally posted by altownsend: The A/C is not working either. For now, I want to get the water temperature sensor to turn the fan on. I take it then that turning the A/C on (even if it isn't fully functional) doesn't power up the rad fan? altownsend JAN 19, 09:23 PM Patrick, Yes, turning on the A/C with the key turned to 'On' position did not turn the fan on. After talking about it and working the logic based on members' input, I thought that it was a 'driver' device (Relay). I replaced the ECM temp switch, cooling fan switch, and the cooling fan relay tonight (Sunday, January 19). I tested the cooling fan at the cooling fan sensor (Green/White wire). I jumped the wire and turned the key to the 'On' position. The fan turned on. So, at the cooling temperate sensor, green wire with white stripe, jumped to ground, the cooling fan activates. problem solved Observation: Before starting the engine a couple of days ago (as I troubleshot the cooling fan issue), I made sure that the antifreeze was topped off. No problem. Today, I pulled the cooling fan temperature sensor. I noticed that the sensor was dry, and it had some red clay like substance (similar to rust material) caked on the sensor probe and in the threads of the hole in the intake. I also noticed that the bottom of the hole where the temp sensor is screwed was dry and had that red clay like substance at the bottom of the hole. When I pulled the ECM sensor, the probe was wet with antifreeze. However, the probe had that red clay color on it. There was no caked substance on it or in the hole. Anyone know what my situation is? I may need to flush the engine and cooling system (Engine block, lines, radiator). Comments please. Gall757 JAN 19, 10:31 PM How can it be 'similar to rust material' and not be rust? Somewhere in the car's past, somebody used only water for a coolant. It should be OK with proper anti-freeze, which will stop any further rusting. cvxjet JAN 20, 12:32 AM Time to flush the cooling system and then fill with proper coolant. altownsend JAN 20, 01:42 AM Yes, It needs to be flushed. I shared that story for others who might encounter the same problem and would be pre-informed that this condition can occur. I will flush on Monday, and I will refill with the proper coolant. So, many of my gremlins are repaired. Just in case the relay issues may have affected the gauges, I will run the engine on Monday to see if any of the gauges show reasonable readings. I noticed that the volt meter is working. I will pursue the oil pressure as the next gauge project. It just so happens that the pressure switch mounted on the engine looks new, so I presume that my problem is the wiring. I read that the middle wire on the connector (sensor) is the gauge wire. I plan to trace it to make sure that I have a good wire to the gauge. If it is not, I will resolve. If it is a good wire to the gauge, I will test the sensor with an ohm meter at the sensor with the engine running and connector off of the sensor. Question: What is a good coolant flush procedure? I have used water only. I have used dish washing liquid (in my Porsche), and I have used dish washing powder (dish washer). Looking for what works good for the Fiero system. With the radiator being up front, is there something in particular I need to do to get a good flush? Thanks altownsend JAN 26, 03:07 PM Update abut the cooling fan (ECM sensor, Cooling fan sensor, cooling fan relay, rust in the system): My little neighbor assistant and I got the cooling fan working with a ground jump at the sensor. Cooling fan sensor and ECM sensor replaced with new with new. Also, I removed the cooling fan sensor after doing a flush with dish washing liquid and tap water. It is now clean, and the block, from as much as I can through the sensor holes, is clean and looking like the inside of an engine block. My buddy used dish washing liquid and tap water to flush his cooling system. It works well. On to other gremlins.