Chevrolet Repair: Engine Cooling Fan doesnt come on, coolant temperature sensor, powertrain control module

Question
On my sons 1994 Chev Cav. 2.2 he noticed that the engine temp rose at stop signs and then that the culprit was the fan wasn't running.  We jumped the battery to the fan, the fan runs.  We purchased and installed a new engine coolant temperature sensor, followed by a coolant fan relay and still the fan doesn't run when the engine comes up to temperature.  We have the service manual for this vehicle and it looks to us like the Powertrain Control Module drops the relay to ground, thus applying power to the fan through the relay.  With a electrical tester it appears the ground is made when the engine comes up to temp.
My son is on a limited budget since he's paying his way through college and doesn't want to rack up a huge repair bill.  To remedy the problem with some backyard mechanics we jumped the relay control wire directly to the fan hot wire, thus the fan runs as soon as the engine is turned on.  However after about a week the engine wouldn't start because it acted like the battery was weak.  Once he diconnected the fan relay the engine started and then he reconnected it.  So apparently our cheap fix isn't working well.  Any input on what the problem may be to why the fan doesn't run as designed would be greatly appreciated.  He wants to buy a timer to install that would timeout once the vehicle is started then the fan would run until the vehicle is shut off.  I know they have these for ac but don't know if they exist for dc.  I'm trying to talk him into just taking it in before we make a bigger problem.
Thanks for any help
Dan

Answer
Hello Dan, The fan on this car is only needed when the A/C is ON or the engine temp goes ABOVE 228 deg. If it doesn't work when this temp comes up (228) then I would just wire a toggle switch under the dash so he can turn it on only when needed. This would be the cheapest way out.


Mark