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To test the fan, first put 12 volts to the fan plug. Pos to one, neg to the other. Does it operate? Yes
You have single or double fans?I had double replaced by a single
Sensor # 2 sends a coolant temp signal to the ECM,........ but the ECM itself actually turns the fan on.
Ok
I can turn on the fan if I connect one of the 2 wires to the neg ?
On dual fan engines, doesn't the ECM control the primary fan, but a fan switch controls the other? Maybe the fan is connected to the wrong relay or other miswiring issues
The fan relay should have 4 wires going to it. A big orange wire that brings 12 volts to the relay from the power block over by the battery, A big black with red stripe wire that sends 12 volts back down to the fan, a small tan or gray wire that is 12 volts with key on, and the green with white stripe small wire that provides a ground either from the ECM or the fan switch to actuate the relay and turn on the fan. If the relay is good, that's all there is to it. Check it all out
Not related to the fan,but sure looks like you may have a standard rotation(CW at front) water pump-the alternator bracket mount lug seen on the pump is normally on 1987-back pumps,serpentine belt water pump is CCW -if wrong rotation,flow will be reduced.
#1 is the cold start injector switch
#2 is the temp sensor for the ECM, That turns the fan on indirectly. ECM uses it to know what the coolant temperature is and then triggers the primary fan relay
No, at the relay, see that the big orange wire is 12 volts. Also insure continuity from the relay down the big black with red stripe wire goes to the pos. side of the fan plug. Other side of the plug should be grounded. Check that with key on the solid color small wire gets 12 volts with key on. If all these things are correct and the other end of the green with white stripe wire is grounded with the key on, the fan will go on. If not either the wiring is bad or the relay doesn't work
the problem is that with the engine very hot
the gauge does not exceed 130 °F
The gauge on your dash is fed by a different sensor. There is a Temp sensor in the drivers side head between the 1st 2 cylinders that is the input for the gauge. The ECM is factory set for some ridiculously high temp like 230 before it will kick the fan on.
Last edited by vinny R; 02-07-2021 at 07:02 AM.
Reason: added info
Not related to the fan,but sure looks like you may have a standard rotation(CW at front) water pump-the alternator bracket mount lug seen on the pump is normally on 1987-back pumps,serpentine belt water pump is CCW -if wrong rotation,flow will be reduced.
+1 Sure looks like you've got the wrong water pump !!!!! I've seen serpentine water pumps with a hole for the coolant hose,... but have never seen a serpentine water pump with the alternator bracket mounting point. This will continue to cause problems until the proper water pump is installed ! \
if the relay is good and I put one of these two wires to the neg, the fan should start
NO: As described earlier: The ECM is what sends the signal & turns on your Primary fan. The secondary fan can be activated by the sensor in the pass side head or by the AC system.
These schematics are from an 88; I don't know what year your car is. If you want to "jump" the relay to get the relay to start the fan:
1: Relay needs Power
2: Relay needs ground
3: ALL wires / plugs must be intact
4: 'jump' NEGATIVE to GREEN/WHITE of the primary fan relay ( OR: to GREEN/WHITE of the secondary fan relay,....... this wire MIGHT be Grey. )
If the relay has Power, Has ground, and you 'jump' the GREEN/WHITE wire and the fan doesn't operate than you've got a bad relay or bad wiring.
+1 Sure looks like you've got the wrong water pump !!!!! I've seen serpentine water pumps with a hole for the coolant hose,... but have never seen a serpentine water pump with the alternator bracket mounting point. This will continue to cause problems until the proper water pump is installed ! \
#2 if the WHITE/GREEN wire you checked was the primary relay,...... ECM &/or wiring is suspect. ( It *COULD* be related to sensor #2 in your picture above; should be 5 volts on YELLOW wire at start-up. At 210 degrees your "sensor #2" should have about 1.5 - 2 volts. The ECM should be turning the fan on @ anything under 1 volt.) Normally when this sensor fails a trouble code code 14 or 15 will set in the ECM.
#3 if the WHITE/GREEN wire you checked was the secondary relay,.... The head mounted temp switch is suspect. ( Can also turn the key to RUN, then turn on the AC to see if that activates the secondary fan, that switched GROUND is on the same circuit as the head mounted switched ground. )
* You want the single fan to operate on the primary relay; you could hook it up to the secondary relay for control off the head mounted switch too, but if you do that you MUST replace the original switch with one closer to 220 degrees. The factory head mounted switch activates @ something like 238 degrees,... that's too hot for a primary fan to start cooling the engine.
Here is a chart so you can OHM test the CTS ( AKA: sensor #2 )
#3 if the WHITE/GREEN wire you checked was the secondary relay,.... The head mounted temp switch is suspect. ( Can also turn the key to RUN, then turn on the AC to see if that activates the secondary fan, that switched GROUND is on the same circuit as the head mounted switched ground. )
Pic #1 appears to be the primary fan relay,... this gets it's "switched ground' to turn on the fan from the ECM. (Large plug @ ECM, PIN 'C1', GREEN/WHITE wire ) OHM test the temp sensor in the intake ( sensor #2 in your pics) to see if it's working correct; or buy another NEW sensor and replace the existing one so you know it's OK. ) if you still don't get the fan when temp is @230 degrees than the ECM or wiring is your problem. Temp sensor wires lead to Large plug @ ECM; BLACK (GROUND) to PIN 'D2' and YELLOW to PIN 'C10'
Pic # 2 appears to be the secondary fan relay,..... it's gets 'switched negative from the switch in the pass side head or when AC is turned on. ( Don't matter if the AC compressor is installed,... if the controller **** is moved to any AC setting the secondary Fan should come on unless the wiring is bad. ) Disconnect the switch on the pass side head and re-test by jumping ground to the plug. ( Wire could be BLACK, GREY, or GREEN/WHITE at the sensor depending on year.) If the fan doesn't work the plug or wiring is bad from switch to relay; if the fan does work then replace the head mounted switch with a new one. ( MUST be rated to turn on at about 220 degrees,..... factory original sensor is NOT OK because it's set to turn on at 238 degrees ! ) I'd recommend a Buick Grand National Temp switch.
Difference between the pump you have and the pump you need is, the direction it turns.
It's a "centrifugal" pump, where the blades just kinda sling the water outwards as they spin; but they're "inclined" one way or the other to favor a direction of rotation. Most designs for that type of pump for liquids, including typical automotive ones, are usually "backwards inclined", such that the center reaches a given "radial" before the outer end. That way, as the blade turns, the coolant is forced up a "ramp" going outwards, as well as just getting slung. If the blades turn the wrong way, that "incline" won't work, and in fact, can even work in reverse, if the inclination is extreme and the substance it's pumping is thick. Usually in an automotive one, it just makes the pump like about 10% as efficient as it should be.
A WP driven by the inside of the belt turns the same way as the engine (a V-belt pump is this way); one driven by the back side of the belt, such as the one in a serpentine (snake-like) system such as yours, turns the opposite way.
You have a V-belt pump, as shown by the bracket mounting boss. It's meant to turn CW viewed from the front, same way the engine spins. Your belt arrangement spins it CCW. It can't possibly work right.
Sorry to hear about your AC. It never ceases to baffle me why people take a "nice" car like these can be, especially a top-of-the-line kind of one like a GTA, and turn them into filthy, BO-infested hilljack wrecks that practically NO member of the other sex will be interested in getting into, by doing that. I strongly urge you to consider restoring it to complete and proper function.
02-06-2021, 12:29 PM
