auxillary fan timer.

[pete2528ca]

Does anyone know where this timer is located?

 

[greg409]

Does anyone know where this timer is located?

If your talking about the condensor fans in front of the radiator, on my '97 they're controlled by the ECU grounding the fan relay for about ten minutes after shutdown. (if engine temp or condensor temp is high)

So the short answer is it's in the ECU I believe


luck,greg

 

[joey]

What year Disco?

 

[joey]

Just looked it up and the ECM (Engine Control Module) does the 10 minute timer for the fans.

 

[joey]

CIRCUIT OPERATION
Condenser Fan Operation (MFI–V8)
The Condenser Fans Motors (M113, M121) on
vehicles equipped with MFI–V8 engines operate
when any of the following conditions occur:
1. Coolant temperature exceeds 100


C (212


F).
2. The air conditioning system is operating.
3. The Engine Control Module (ECM) (Z132)
determines that fuel temperature exceeds
70


C and coolant temperature exceeds 110


C
after engine shutdown. When this occurs, the
fans are turned on for approximately 10 minutes
after the engine is shut off.
Operation with High Coolant Temperature
(MFI–V8)
When the Ignition Switch (X134) is in position II,
battery voltage is applied to the Ignition Load Relay
(K127). The relay is energised, applying battery
voltage to the Condenser Fan Relay (K109) and the
Fan Control Module (Z118). If the coolant
temperature exceeds 100


C (212


F), the Condenser
Fan Coolant Temperature Switch (X113) closes and
energises the Condenser Fan Relay (K109) by
applying ground to the relay’s coil. When the relay is
energised, voltage from fuse F3 is applied to the
Condenser Fan Motors (M113, M121) through the
relay’s contacts.
Fan Operation with A/C (MFI–V8)
With the Ignition Switch (X134) in position II, battery
voltage is applied to the Ignition Load Relay (K127).
The relay is energised, applying battery voltage to
the Condenser Fan Relay (K109). When the Front
A/C Switch (X225) is turned on and the Front Fan
Speed Switch (X247) is turned to positions I, II, III, or
IV, ground is applied to terminal 86 of the Condenser
Fan Relay. The relay energises, applying battery
voltage from fuse F3 to the Condenser Fan Motors
(M113, M121).
Operation with the Engine Off (MFI–V8)
The Engine Control Module (Z132) monitors fuel
temperature and coolant temperature through
sensors. When the ECM determines that fuel
temperature is above 70


C and coolant temperature
exceeds 110


C after engine shutdown, the ECM will
command fan operation for approximately 10
minutes. The ECM turns on the fans by momentarily
grounding the Fan Control Module (Z118) through
the BG wire. When the timer unit is grounded, it
starts a solid state timer and begins to apply ground
from its terminal 9 to the Condenser Fan Relay
(K109) through the BP wire. With the Condenser
Fan Relay energised, voltage from fuse F3 is applied
to the Condenser Fan Motors (M113, M121) through
the relay contacts.

 

[pete2528ca]

Sorry guys, I am freaking out so much trying to get those fans to work.

1997 Disco.

I am assuming it is an SFI engine because on the front tag in the engine bay where the evap family code is listed it says SFI and a bunch of numbers. In any case it is a 4.0

There is no fan switch in the thermostat housing.

I have the rave guide and for SFI it basically says...

the ignition load relay powers the fan relay that powers the fans.

The ECU grabs a fuel temp reading and a coolant temp reading to determine the temperature of the engine and runs the fans.

They come on fine when the A/C is on, but do not come on as auxillary fans or after the engine is shut down.

WHAT NEXT?

Anyone have to deal with this before?

Thanks again.

Pietro

 

[joey]

If they come on with the A/C, then it sounds like they are doing the job... they will only stay on after engine shut down if the engine is hot enough. How hot is the engine getting?

 

[pete2528ca]

I have never checked the actual temperature, but on the guage it is on the lower part of half.

 

[joey]

Sounds like it is working