Update. Disconnected battery again checked all rcm connections. Restart car AC works cooling fan doesn’t come on for 5 minutes. AC cycles fan sort of cycles intermittently yet when engine temp approaches the 3/4 mark on gauge fan won’t come on. This is getting nuts. New Fan and new controller?

 

THis is not an update, this is a new thread. You are making it hard to help you by starting a new thread - where is the old thread that will bring us 'up to speed' on the history here?

Sounds like you either have a bad cooling fan motor, bad Fan Controller or blown 50 amp fuse. (That, or the ECM/PTCM is bad, but the possibility of that is about 1 in 250,000.)
Does the little "radiator light" ever come on during any of the above?

 

Sorry Pizza Guy, I’m new and apparently my first post didn’t go up. Here is the story. A month ago car battery died at a store. Jumped it and drove it home. Alternator wasn’t charging, smelled fried. Replaced battery and alternator. At the same time I decided to
replace water pump, thermostat, pulleys, belt, hoses and radiator. Started car all good. Then AC decided not work within a few days. Diagnosed a bad AC clutch. Replaced AC compressor, drier, and expansion valve. Fixed AC for a day. Then AC intermittently wouldn’t work. Only while driving would it blow cool air, at idle warm. Checked under hood cooling fan not turning no matter whether AC on or engine temperature getting hot. Replaced both the fan and fan controller still no go. I saw a post about the RCM solder and relays. Figured I’d try it. Disconnected battery pulled RCM did the resolder on connections, cleaned relay contact points, cleaned all fuse connections. Reinstalled it and started car. Worked perfectly on 10 mile drive, AC ice cold engine temps stayed in the midrange on gauge. Let car sit idling in driveway for 15 minutes AC nice and cold cooling fan running. Then this morning upon start up, turn on AC no cooling fan, engine temperature increased fan came on for 2 seconds shut off. Drove it AC worked engine temp normal. Stopped car at traffic light engine warmed up AC stopped blowing cold. Drove away got a mile and engine temp dropped AC blew cold until I stopped for another traffic light. Got home let idle cooling fan will not kick on no matter what the engine temperature is or with AC on. Is it possible the RCM is just bad? I’m running out of ideas. Thanks, Sal

 

With all the time and money already spent, why stop short of a new RCM...

 

Thanks. I am considering purchasing a new one. Just trying to make sure it will solve the problem. Lol. I’ve already put tons of new parts in it. 😂 would you happen to know how often the engine cooling fan cycles? I’m sure it’s not designed to run full time.

 

You are almost right, but wrong.

The cooling fan runs:
... At a minimal speed anytime the A/C is turn on, this is to draw some air across the condenser to cool it.
... At a minimal speed when engine temperature reaches something around 200F, should the temperature continue to increase, the fan will speed up in an effort to control coolant temperature.
... NEVER with engine temperature below 200F and the A/C turned off.


The design is simple:
The ECM and the FCM carry on a conversation ANYTIME the key is 'on'. Every 200 or 400 milliseconds (I once knew exactly, but forgot) the ECM says "Are you there?" The FCM responds with "I'm here".
If the ECM sees engine temperature rising above around 200F, it tells the FCM to run the fan at slow speed (it does this by modifying the "Are you there?" message with a longer pulse which indicates the fan should run); if the A/C is turned on, it tells the FCM to run the fan at slow speed. If the coolant temperature rises, the ECM tells the FCM to speed up the fan by making it's pulses to the FCM even longer.

If the ECM does not get an "I'm ok" response, it will turn on the "low coolant light".
If the FCM does not hear from the ECM, it speeds the fan up to Warp Speed (to protect the engine because it does not know the temperature of said engine).

If you have not "Low coolant" light, then the ECM thinks all is OK. This means the FCM is responding and the ECM sees the response.
SO, either the ECM is not telling the FCM to run the fan, or the FCM is just not doing it's job.

Check the 50amp fuse to the FCM (in small fuse box next to battery).
if it's ok, then:
Replace FCM.

I have a hard time beleiveing the ECM is the cause of this but it could be. But tha'ts around a $2000 repair IF you can find a new ECM. If it goes that far, yank the ECM and send it to one of the companies that work on them.

 

Thanks pizza guy. 50 amp fuse is good. FCM is new and so
is fan. Right now the fan is doing the on and off dance for a few seconds and engine temps are normal as well as AC. Must be some sort of electrical gremlin. I’ll update again if it fails.

 

Your first post was at 8.00 am today, now you have an up date as a new thread. You first thread did upload OK.

 

Thank you. Well the fan and ac worked intermittently for about an hour. Then fan quit again. I jumped the fan where it’s running full time with engine and AC on. Engine is running at normal temperature and AC cold. I’m thinking now the new fan Control Module is faulty.

 

Get a new fan while you are at it, the fan will not run at full speed for too long.

 

Did that. The fan is only 2 weeks old as is the FCM. Sent FCM back to exchange for another thinking it’s faulty. You guys are great with the replies and info. Will update when new FCM arrives.

 

Did you ever get that new FCM? Was your first replacement really faulty? What happened

 

Secret007 has decided to keep it secret.

 

That guy joined the forum just to get his question answered, not to return the favor by helping others. We get that a LOT here.
I'd imagine the FCM was bad and when he got a new one, it was fixed so he never returned. While his posts seemed appreciative, this was all a one-way thing with him, once he got the problem fixed, he didn't need us anymore.

Makes ya really want to help new members, doesn't it? (Insert rolling eyes emoticon here...)

 

Where have you been? I don't remember seeing any post of yours in maybe two-three weeks

 

Hahaha! Welllllll you two (pizzaguy and onehundred80) are true OG's on this forum. I almost believe I see at least 1 of you- in EVERY THREAD I read!
Honestly, I'm glad you're both still around.... Thank You both, for all the time and insights you provide us.