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Radiator cooling fan?

Tiny
PETEY321
  • MEMBER
  • 2008 DODGE GRAND CARAVAN
  • 3.8L
  • V6
  • 2WD
  • AUTOMATIC
  • 141,000 MILES
In troubleshooting transmission wiring I pulled these codes relating to cooling fan- 1.P0693 Fan 2 Control Circuit Low. 2. P0691- Fan I Control Circuit Low. When I Pull fuse # 28(NGC/Trans FD (Batt), the radiator fan comes on, sometimes with relay chatter, sometimes without. If I pull relay mounted b/w radiator and dr. Sd. Headlight assy. It comes on without any relays chattering. Thus, it doesn’t seem normal to me, but I wouldn’t know. Is it normal? I’m suspicious that it’s tied to my transmission problem.

Thanks,
Paul
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Sunday, September 11th, 2022 AT 12:26 PM

13 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,188 POSTS
Hi,

Have you switched the relay with a different one from the box to see if the same thing happens?

I ask because this could be a short, the relay itself, or the totally integrated power module (TIPM). I don't know if you are familiar with the TIPM, but they are known to have issues. Actually, the module doesn't, but the connectors to it do.

The pins in the connectors are small and overcrowded. As a result, it isn't uncommon for them to break due to corrosion or vibration.

What is happening with the transmission? Let me know so I can tell if they could be related.

One other note. The relay near the radiator is the high-speed relay. If that is shorted to power, it can cause the low-speed relay to act oddly. The low-speed relay is in the power distribution box.

Do me a favor. With the key off, remove the relay near the radiator. Check pin 5 in the connector for resistance. Connect your ohm meter between the pin and a known good ground location. If it is below 100 Ohms, we have a short.

Here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-wiring

Let me know.

Joe

See pic below.
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Sunday, September 11th, 2022 AT 6:43 PM
Tiny
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Here is a photo of the high-speed radiator fan relay resistance you requested. Meter set to lowest ohm scale that gave a reading.

I’m going to write a separate reply describing symptoms and action taken thus far.
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Tuesday, September 13th, 2022 AT 2:22 PM
Tiny
JACOBANDNICKOLAS
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Hi,

That's slightly above 100 Ohms so it should be okay. Have you tested the relays?

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Let me know.

Joe
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Tuesday, September 13th, 2022 AT 7:34 PM
Tiny
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I removed the relay and connected pins 85/86 together to produce the audible click of electromagnetic switch.

While pins 85/86 are still jumped together and relay out of circuit I measured resistance across pins 30/87. On 20M scale ohms started at 1.20 and trickled down to.54 slowly. On 2M scale ohms started at.122 and increased one digit at a time slowly reaching.889 and dropping down to.064. Before stabilizing there. I attached a video of a portion of the resistance measurement.

Thanks,
Paul
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Friday, September 16th, 2022 AT 12:36 AM
Tiny
JACOBANDNICKOLAS
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Hi,

For some reason, I can't get the video to play. I have a question. When you had the relay out and checked the secondary side for resistance, was power still being applied to the primary side? If it wasn't, that should be an open circuit.

Let me know.

Joe
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Friday, September 16th, 2022 AT 8:16 PM
Tiny
PETEY321
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Power was supplied to 85/86 while checking resistance on 30/87. I’ll try to upload the video again.
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Friday, September 16th, 2022 AT 11:36 PM
Tiny
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One more time.
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Friday, September 16th, 2022 AT 11:40 PM
Tiny
PETEY321
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Testing another relay (this is actually the low circuit relay for radiator fan, it had dropped into the engine compartment and couldn’t find it on last replies. I substituted in previous test). That being said, this one acting totally different. It will only read on the 20M scale. It bottomed out at 5.45 and after a few minutes it began climbing slowly. It’s currently reading 8.56 and still increasing. I’m assuming this is bad. (9.16 now and holding).
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Saturday, September 17th, 2022 AT 11:44 AM
Tiny
PETEY321
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Testing another relay (this is actually the low circuit relay for radiator fan, it had dropped into the engine compartment and couldn’t find it on last replies. I substituted in previous test). That being said, this one acting totally different. It will only read on the 20M scale. It bottomed out at 5.45 and after a few minutes it began climbing slowly. It’s currently reading 8.56 anc stir increasing. I’m assuming this is bad.(9.16 now and holding).
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Saturday, September 17th, 2022 AT 11:44 AM
Tiny
PETEY321
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On TIPM for relay K10 (ASD relay) and mini fuses 19 and 20, with a circuit test light that shows either red or green, the sockets for these show ground, but it’s a weak green Illumination compared to other fuses that show a strong bright green light.
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Saturday, September 17th, 2022 AT 6:10 PM
Tiny
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Fuses 19 / 20 (ASD #1 and #2, / ASD #3 respectively).
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Saturday, September 17th, 2022 AT 6:16 PM
Tiny
PETEY321
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This should have been in the last reply.
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Saturday, September 17th, 2022 AT 6:19 PM
Tiny
JACOBANDNICKOLAS
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Do you feel the ASD click indicating it is functioning? The idea that you have a very weak ground could be the issue. Have you checked the connectors?

Let me know.

Joe
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Saturday, September 17th, 2022 AT 10:15 PM

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