Coolant fan relay... '88 Corsica 2.0

i will now read the online service manual to you.
https://eautorepair.net/Marketing/Default.asp

blower fan located where. dash heater blower fails
or radiator fans of some odd kind added later.
coolant fan or dash? there are 2 coolant fans and 3 relays to run them and all 3 relays, can fail and coolant fans blow for ever and ever. fuse 6 kills the relay coils. only, so if relay is welded fans blow endlessly. even if bcm is removed from the car.
on the other and the heater blower is 100% controlled by the BCM

so car engine starts and runs and drives ok right.
when did car last run perfectly> , or seen ever ?
service manuals for 88 cars are not easy to find
means real oem manuals, best. 35 years old !
no digital then ,just a huge paper bound book, remember?
holy moly this 88' has a body controller here, bcm , relic amazing thing.
facts: 1988
here is proof

Cooling fan switch ? The cooling fans (2) on that motor are controlled by three relays . A coolant temp. sensor gives temp info to the PCM - engine computer .
During high speed operation the PCM supplies the ground path for the cooling fan 1 relay through the low speed cooling fan relay control circuit. After a 3 second delay, the PCM supplies a ground path for the cooling fan 2 relay and the cooling fan S/P relay through the high speed cooling fan relay control circuit. This energizes the cooling fan 2 relay coil, closes the relay contacts, and provides a ground path for the left cooling fan. At the same time the cooling fan S/P relay coil is energized closing the relay contacts and provides battery positive voltage from the cool fan 2 fuse on the cooling fan motor supply voltage circuit to the right cooling fan. During high speed fan operation, both engine cooling fans have their own ground path. The result is a parallel circuit with both fans running at high speed.
The PCM commands Low Speed Fans on under the following conditions:
• Engine coolant temperature exceeds approximately 106°C (223°F).
• When A/C is requested and the ambient temperature is more than 50°C (122°F).
• A/C refrigerant pressure exceeds 1 310 kPa (190 psi).
• After the vehicle is shut off if the engine coolant temperature at key-off is more than 140°C (284°F) and system voltage is more than 12 volts. The fans will stay on for approximately 3 minutes.
The PCM commands High Speed Fans on under the following conditions:
• Engine coolant temperature reaches 110°C (230°F).
• A/C refrigerant pressure exceeds 1 655 kPa (240 psi).
• When certain DTCs set .
Watch this video ,it shows how it works !
Relay Driven Dual Cooling Fan Diagnostics

most 93 to 95 have viscus clutch not electric fan (A/C evap fan sure) but some do have the Aux fan too. and the PCM reports DTC errors, if the relay fails. did it? report that?
ok the 95 XJ with 4.0 does have fan.... have FSM in hand.
If the ECT has air pockets it well never report hot temps.
it will not energize the Fan relay if the ECT fibs. for any reasons.
page 35 Chapter 7
the viscous fan locksup at (165° to 180° F).
the electric fan is as follows.
i guess you never looked in the PDC before or its lables
"The fan is controlled by the cooling
fan relay, which is located in the power distribution
center (PDC). For the location of relay within
the PDC (Fig. 41), refer to the label on PDC cover"
and now AUX Fan , quote2.
"When coolant temperature is above 88°C (190°F),
the powertrain control module (PCM) provides a
ground path for the fan relay. This ground is provided
through pin/connector #31 of the PCM 60-way
connector. Battery voltage is then applied to the fan
through the relay. When coolant temperature is below
88°C (190°F), the PCM opens the ground path to
the relay. This will prevent the cooling fan from being
energized.
Whenever the air conditioning is operated, the
PCM engages the auxiliary cooling fan

given these facts? why not turn on A/C and end the guessing.

I use my scan tool , and innova 3140 for jeep OBD1.
it shows me what he pcm sees for ECT readings
if the engine is at 100C and the ECT shows way lower
its bad. or has air pockets around it,
no ect runs in air and works, none,.
if say the ECT is at 100C and the fan relay is not closed
the relay is bad or ECU driver to it blown. (bad ecu)
if the relay coil is hot, and the fan is not the relay is bad.

if the relay is closed and 12vdc out of it, then fan is dead.
if the fan is good (hot wired), and the relay out is hot , the wires are bad from relay to fan.
a $10 voltmeter and the guessing ends.

Well I'm sure there are kits to wire up electric fans on cars that are not designed for one.
You would need a relay and something to turn the relay on. A coolant sensor won't do the trick, the sensor is what tells the computer the engine temp, and the computer decides when to ground the fan relay.
You would need a temp switch that is designed to close at say 220 degrees to ground or power the fan relay.
The fan motor would have ground and power wires.

The computer takes info from the engine temp sensor to decide if the fan is needed. The temp sensor is on the intake manifold and has two wires. Check the relay too.

ok this might sound crazy but you say you smell coolant but never said if you checked to see if it was full posible bad coolant temp sensor or no coolant passing the sensor please more info on coolant usually if low coolant fan will stay on however you say you smell coolant. If the coolant sensor is bad fan wont command on it will have a high resistance a low coolant temps and low at high temps. I would check sensor since its obviously getting hotter than half way if you dont have coolant leak the relay behind the head light by the way is a common problem I would have just changed it if its original and it grounds to body thats why it is riveted however you can bolt them. Hope this helps check for thermostat opening at right temps to.

if the fans were working good before. check the fuses or fan relay in fuse box. if ok. see if power is getting to fan( car on engine off ) at the fan connection. to test fans if need be. run a wire from positive on fan motor to positive on battery, then ground other connection to a suitable ground or the negative post on battery. if the fans are ok. here are a few causes--- defective thermostat stuck open ( engine does not get hot enough to turn fan on ) . a failed fan relay, or a bad fan motor! or engine coolant tempurature sensor is bad. have a good day !!

Trouble code P1652 means: Cooling Fan 2 Relay Control Circuit Malfunction

I would start by checking power supply to the cooling fans,making sure the coolant system is full,& using a scn tool to verify the proper operation of the cooling fan system.Here is some info to help you.

The Powertrain Control Module (PCM) controls the operation of the cooling fans. This is accomplished by providing a ground path for the cooling fan relay coils within the PCM. The relay contacts will close and complete the circuit between the fusible link at the battery junction block and the fan motors. Whenever there is a fan ON request both fans will be running.

Power for the fan motors is supplied through a fusible link at the battery junction block. Battery positive voltage is applied to the cooling fan relay contacts and coils. The cooling fan relays are energized when current flows through the relay coils to ground at the PCM. The cooling fan relay #1 control circuit is used for low speed cooling fan operation. The cooling fan relay #1 control circuit and the cooling fan relay #2 and #3 control circuit are both grounded for high speed fan operation. The cooling fan relay control circuits are monitored by the PCM. Before using the Electric Cooling Fans diagnostic tables be sure to perform the Powertrain On-Board Diagnostic System Check. If diagnostic trouble codes P1651 or P1652 are present, use the appropriate DTC diagnostic tables prior to performing Electric Cooling Fans diagnostics.

Important: When certain Diagnostic Trouble Codes (DTCs) are present, the PCM may command the cooling fans to run all the time. It is important to perform the Powertrain On-Board Diagnostic System check prior to diagnosing the engine cooling fans.The PCM will complete the ground path for cooling fan relay #1 under any of the following conditions:
- When engine coolant temperature exceeds 105°C (221°F)
- When A/C is requested and ambient temperature is greater than 10°C (50°F)
- When A/C refrigerant pressure is greater than 190 psi (2 volts)

For high speed cooling fans operation, the PCM will delay control of the cooling fan #2 and #3 relays for 6 seconds. The 6 second delay ensures that the cooling fan electrical load will not exceed the capacity of the system. The PCM will complete the ground paths for cooling fan relays #1, #2, and #3 under any of the following conditions:
- When engine coolant temperature exceeds 113°C (235°F)
- When A/C refrigerant pressure is greater than 275 psi (2.9 volts)

If a problem that involves the low speed cooling fan relay control circuit (cooling fan relay #1 control) exists, DTC P1651 should set. If the problem affects the high speed cooling fan relay control circuit (cooling fan relay #2 and #3 control), DTC P1652 should set. A problem with the ECT sensor should set DTC P0117, P0118, P1114, or P1115. Any of these DTCs will affect cooling fan operation and should be diagnosed before using the Electric Cooling Fan Diagnosis table. The Electric Cooling Fan Diagnosis table should be used to diagnose the PCM controlled cooling fans only if no DTC is set.
Hope this help to solve your poblem (remember rated and comment this help).

dont think so,seem to remember a reostat somewhere at the bottom of the rad right hand side ,check for earth problems as well ,sorry if vague but i seem to be forgetting things as i get old .

Sensor on the engine sends info to the computer that triggers fan relay and sends power to fan. Most often problem is sensor or relay but quick check fan itself by hot wiring it to the battery Polarity is not an issue...if you get wrong it will run backwards. If it does not run, it's bad.