Yet another radiator fan issue - DodgeIntrepid.Net Forums - Dodge Intrepid, Concorde, 300m and Eagle Vision chat
 2Likes
Reply
 
LinkBack Thread Tools Rate Thread Display Modes
post #1 of 44 (permalink) Old 09-30-2018, 11:23 AM Thread Starter
Intrepid Fan
 
Join Date: Aug 2017
Location: Tampa, FL
Posts: 217
Feedback: 0 / 0%
   
Yet another radiator fan issue

I was driving today and smelled a burnt plastic smell like my RFI module burned out again... and a/c went warm. Cooling fans turned off.

Now when I start the car, the fans run for about 5 seconds then turn back off even with a/c on. Getting really sick of this issue. RFI module doesn't look melted like before. Fans seem to work but won't stay on.

I'm most likely going to have to wire them to the battery directly. If no one has any ideas otherwise, I'd like some tips on how to do that, without a toggle switch for now.

The coolant temp sensor is new and working, rad fans are only a few months old, fuse looked good, I swapped the relays with the wipers and no change. Fans run for 5-15 seconds after starting then they just turn off with a/c on. Only other thing I can think of is the ECM. I don't think it's a wiring short because the fans do turn on for some seconds. When my RFI module was busted, the fans would not turn on at all.

Any ideas?

Last edited by codyj; 09-30-2018 at 11:56 AM.
codyj is offline  
Sponsored Links
Advertisement
 
post #2 of 44 (permalink) Old 09-30-2018, 12:48 PM Thread Starter
Intrepid Fan
 
Join Date: Aug 2017
Location: Tampa, FL
Posts: 217
Feedback: 0 / 0%
   
Since the fans do turn on, I'm wondering now if it could just be a/c related. Don't think car was at a high enough temp to run the fans with a/c off/broke so they might work, will test later.
codyj is offline  
post #3 of 44 (permalink) Old 09-30-2018, 03:50 PM Thread Starter
Intrepid Fan
 
Join Date: Aug 2017
Location: Tampa, FL
Posts: 217
Feedback: 0 / 0%
   
I jiggled the cooling fan harness and the a/c transducer and now it is working again... nothing seemed loose so don't know if that 'fixed' it or what. Old cars I tell you.
codyj is offline  
Sponsored Links
Advertisement
 
post #4 of 44 (permalink) Old 10-01-2018, 12:10 AM
Woober Goobers!

 
Ronbo's Avatar
 
Join Date: Mar 2005
Location: Tiny Pebble, AR
Posts: 47,791
Feedback: 44 / 100%
                     
Wonder if you have an A/C Transducer that's starting to go out. Causes problems in the 2nd gen LH cars also.
Ronbo is offline  
post #5 of 44 (permalink) Old 10-01-2018, 08:41 AM Thread Starter
Intrepid Fan
 
Join Date: Aug 2017
Location: Tampa, FL
Posts: 217
Feedback: 0 / 0%
   
I think it is possible. But this is very similar to what happened before my RFI module shorted out. My fans would just shut off and car would begin to overheat, then they would work again. I'd feel much better if I could find a Mopar fan assembly, but things are working today... so far.
codyj is offline  
post #6 of 44 (permalink) Old 10-02-2018, 11:36 AM Thread Starter
Intrepid Fan
 
Join Date: Aug 2017
Location: Tampa, FL
Posts: 217
Feedback: 0 / 0%
   
It is doing it again. Just going to have to take it into a shop I guess. I don't have a clue what it is this time.
codyj is offline  
post #7 of 44 (permalink) Old 10-02-2018, 12:37 PM Thread Starter
Intrepid Fan
 
Join Date: Aug 2017
Location: Tampa, FL
Posts: 217
Feedback: 0 / 0%
   
I'm trying to logically think through this issue.

* Fans work immediately after starting vehicle for 5-10 seconds every time, then turn off. I feel this rules out an electrical issue at the fans themselves.
* The issue 'fixed' itself some how. I drove yesterday and half of today with no problems. Fans shut off mid-drive today.
* Coolant temperature sensor works normally, I just replaced it a few months ago as well.
* I don't think the a/c pressure transducer faulting would cause both fans to stop working.
* a/c compressor clutch engages when starting vehicle, blows cold air for a few seconds until fans turn off.
* Heat works and there does not appear to be any air in the system. Coolant level stays constant between drives.
* No CEL
* Looking at wiring diagram, the only logical thing I can think of is a shorted connection to the PCM, or the PCM itself is faulty.
codyj is offline  
post #8 of 44 (permalink) Old 10-02-2018, 02:55 PM Thread Starter
Intrepid Fan
 
Join Date: Aug 2017
Location: Tampa, FL
Posts: 217
Feedback: 0 / 0%
   
The car has cooled off and now the fans seem to be working again. It's a very weird issue. I'm wondering if the relays could be failing or overheating. But I've swapped them around once and the issue arose again which leads me to believe it is not related to the relays.

I also don't think the PCM would be affected by engine temperature. It also doesn't make sense since with the a/c on, the fans should come on as well regardless of engine temp. And why would they work on start up only to not work seconds later even with a/c on or engine over 220F...?

It seems there is at least one thing ruling out each component.
codyj is offline  
post #9 of 44 (permalink) Old 10-02-2018, 03:07 PM
Woober Goobers!

 
Ronbo's Avatar
 
Join Date: Mar 2005
Location: Tiny Pebble, AR
Posts: 47,791
Feedback: 44 / 100%
                     
Get your multimeter out and start probing voltages when it starts acting up.
peva likes this.
Ronbo is offline  
post #10 of 44 (permalink) Old 10-02-2018, 05:30 PM
Intrepid Pro
 
Join Date: Feb 2002
Location: Virginia, U.S.
Posts: 15,844
Feedback: 4 / 83%
                     
Quote:
Originally Posted by Ronbo View Post
Get your multimeter out and start probing voltages when it starts acting up.


Quote:
Originally Posted by codyj View Post
...It also doesn't make sense since with the a/c on, the fans should come on as well regardless of engine temp. And why would they work on start up only to not work seconds later even with a/c on or engine over 220F...?...
Here’s something to consider (assuming the fans work like on 2nd gen. LHs):
The fans operate on two speeds. There are two relays that control that. Fans off is with both relays de-energized. Low speed is with one of the relays energized. High speed is with both relays energized.

If the low speed relay is not working for whatever reason (bad relay, bad wire, bad PCM), the fans will stay off when they should be running at low speed, and when high speed is called for, they will operate at a lower speed (probably very close the the normal low speed).

So - if normally, high speed is commanded at startup, the fans will run at something similar to low speed instead, and then they’ll turn off. Then, as the engine heats up, the fans will not turn on at all until the engine gets hot enough to call for high fan speed, at which time they will run at the pseudo-low speed, and will never run at true high speed no matter how hot it gets.

So, it’s a long shot, but, again, consider that as a possible explanation.

If the normal startup run speed is low speed, then you can dismiss my suggestion.


'98 LXi - Later Concorde gages (black w/ chrome rings)/'99 LX - LHS gages (white) - HIR bulbs
peva is offline  
post #11 of 44 (permalink) Old 10-02-2018, 06:19 PM
Woober Goobers!

 
Ronbo's Avatar
 
Join Date: Mar 2005
Location: Tiny Pebble, AR
Posts: 47,791
Feedback: 44 / 100%
                     
When in Doubt Whip It Out..........












The Multimeter that is!

Think you have a wiring or PCM issue but I'm no expert in 1st Gen cars. Possible brittle wiring harness or connector/connector pin issues.
Ronbo is offline  
post #12 of 44 (permalink) Old 10-02-2018, 06:26 PM
Woober Goobers!

 
Ronbo's Avatar
 
Join Date: Mar 2005
Location: Tiny Pebble, AR
Posts: 47,791
Feedback: 44 / 100%
                     
* a/c compressor clutch engages when starting vehicle, blows cold air for a few seconds until fans turn off.

Possible Control issue. The fans should come on when the A/C engages. PCM? PCMs have to be cheap and plentiful for the 1st Gens?

It seems you're reluctant to take Voltage readings for some reason and so far have just been "Throwing" parts at the problem in a Shotgun approach.

The fans turning on at startup indicates most if not all of the circuit is working. After that it's a control issue. The PCM is ultimately going to control the Cooling Fans.

Have you carefully checked all the ground wires at the PCM and to the Engine Block?

What does the Temp Gauge reading show when all this happens. Is it correct? Showing high temp when the A/C cuts out or the cooling fans stop?

JJI=Just Junk It, LLC!
Member of the Sold SRT-8 Magnums of DI.net Club!
Perky Jerky for Everyone!!
Crazy Rons House of Mega Deals
Ronbo is offline  
post #13 of 44 (permalink) Old 10-02-2018, 07:18 PM Thread Starter
Intrepid Fan
 
Join Date: Aug 2017
Location: Tampa, FL
Posts: 217
Feedback: 0 / 0%
   
Quote:
Originally Posted by peva View Post


Here’s something to consider (assuming the fans work like on 2nd gen. LHs):
The fans operate on two speeds. There are two relays that control that. Fans off is with both relays de-energized. Low speed is with one of the relays energized. High speed is with both relays energized.

If the low speed relay is not working for whatever reason (bad relay, bad wire, bad PCM), the fans will stay off when they should be running at low speed, and when high speed is called for, they will operate at a lower speed (probably very close the the normal low speed).

So - if normally, high speed is commanded at startup, the fans will run at something similar to low speed instead, and then they’ll turn off. Then, as the engine heats up, the fans will not turn on at all until the engine gets hot enough to call for high fan speed, at which time they will run at the pseudo-low speed, and will never run at true high speed no matter how hot it gets.

So, it’s a long shot, but, again, consider that as a possible explanation.

If the normal startup run speed is low speed, then you can dismiss my suggestion.
I did consider something like this. I have swapped the relays again with the fuel pump and auto shutdown. Before I swapped with the wipers. Everything is working normally for all the other relayed components as well.

Before my RFI module shorted out, the symptoms were very similar. After it shorted out, only my a/c fan was working but before that, sometimes the fans would turn off as they do now. Both fans working when starting the car is what is throwing me off. The RFI module doesn't have the ability to start/stop the fans so it's ruled out.

The fans are getting voltage normally from the PCM and through the relays, then the PCM decides they don't need to be on via the coolant temp sensor's voltage _AND_ the a/c system. There must be a hub where those two components go to that has failed since neither of their signals are influencing the PCM, and the only one I know of is the PCM itself. If one component, either the coolant temp sensor or a/c compressor turned the fans on, the solution is easier. But since both have no effect on the fans, I'd figure either relays or PCM and based on what I've seen, the relays are fine.

If so, my only question would be could the PCM intermittently do this or should it be more of a binary failure; like it either works or it doesn't anymore? Unfortunately, the only way to know is to swap out the PCM for another in which case I'll have to hunt one down.
codyj is offline  
post #14 of 44 (permalink) Old 10-02-2018, 07:22 PM Thread Starter
Intrepid Fan
 
Join Date: Aug 2017
Location: Tampa, FL
Posts: 217
Feedback: 0 / 0%
   
Quote:
Originally Posted by Ronbo View Post
* a/c compressor clutch engages when starting vehicle, blows cold air for a few seconds until fans turn off.

Possible Control issue. The fans should come on when the A/C engages. PCM? PCMs have to be cheap and plentiful for the 1st Gens?

It seems you're reluctant to take Voltage readings for some reason and so far have just been "Throwing" parts at the problem in a Shotgun approach.

The fans turning on at startup indicates most if not all of the circuit is working. After that it's a control issue. The PCM is ultimately going to control the Cooling Fans.

Have you carefully checked all the ground wires at the PCM and to the Engine Block?

What does the Temp Gauge reading show when all this happens. Is it correct? Showing high temp when the A/C cuts out or the cooling fans stop?
I haven't thrown any parts at it yet and the only reason I haven't taken voltage readings is because as you said, the circuit is working each time I start the car. So I agree it must be some kind of control issue. I'm sure I can find a cheap one.

When the fans cut out, the engine temp is normal. I notice the a/c goes warm and that's how I know the fans have cut out. From there I turn the heat on and pull over, sure enough fans are off even as the engine temp has risen to the point they should come on. Then I start the car again, fans kick on for 5 seconds and then go off even with a/c on and engine temp in the range the low speed fans should turn on. Just doesn't seem wiring related to me if the circuit works each time.

Looks like I'll be getting a PCM.
codyj is offline  
post #15 of 44 (permalink) Old 10-02-2018, 07:28 PM
Woober Goobers!

 
Ronbo's Avatar
 
Join Date: Mar 2005
Location: Tiny Pebble, AR
Posts: 47,791
Feedback: 44 / 100%
                     
When I say a wiring issue....it can be a bad/intermittent connection somewhere in the wiring harness. By that I specifically mean in the area of the PCM.

Maybe try disconnecting the PCM and clean the connectors with Contact Cleaner, etc. And again...carefully check the ground connections. Ground straps, ground wires, etc.
Ronbo is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the DodgeIntrepid.Net Forums - Dodge Intrepid, Concorde, 300m and Eagle Vision chat forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

Member names may only be composed of alpha-numeric characters. (A-Z and 0-9)

!!ATTENTION ADVERTISERS!! If you intend on advertising anything on this forum, whatsoever, you are required to first contact us here . Additionaly, we do NOT allow BUSINESS NAMES unless you are an Authorized Vendor. If you own a business, and want to do sales on this site via posting or private message, you will need to follow the rules. Shops, Stores, Distributors, Group Buys without being authorized will see your account terminated.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes Rate This Thread
Linear Mode Linear Mode
Rate This Thread:



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome