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Electric fans aren't coming on....What temp should they come on??

Old 07-13-2015, 05:04 PM
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Default Electric fans aren't coming on....What temp should they come on??

For my 2003 5.3L 1500 WT, I bought all new stuff new radiator, fans, harness, and Lew turned the PCM on. Installed the harness (BP Automotive) according to the instructions (blue connector pin 42) and (red connector pin 33). The issue I'm having, is I don't know if it works or not. It's 80 deg. out, but the truck driving around town has never got over 197 deg. In doing a little looking around online, it doesn't look like the fans turn on until around 216-220 deg. Is there anyway to test them? Neither come on when I turn the AC, but I've also seen where people say that they won't turn on until 220 I've also seen people say that they turn on right away.

Thanks
Old 07-13-2015, 06:34 PM
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What temp did they set the tune to command the fans on at.
Old 07-13-2015, 08:21 PM
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Whatever temperature the stock ones come on. I just asked for the fans to be turned on thinking that the electric fans would kick on at about 190. With the clutch fan the truck never went over 190
Old 07-13-2015, 09:12 PM
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On a vehicle not originally equipped with E fans, The default setting is something like 284*

You have to change the settings when you enable the fans. You would have to ask your tuner what they were set to.
Old 07-13-2015, 11:40 PM
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Finally after driving up and down hills for awhile and coming back to the driveway and sitting the temp went to 227 before I turned it off. The fans did not come on.
I've asked Lew what temp he set them to come on at, but won't hear back from him until tomorrow. Only other thing I can think of being the issue is well two issues, one being that when I put the wire in spot 33 it kinked a bit (maybe breaking the wire on the inside) I ended up buying a d-sub insertion tool to put it in properly after that. The second being a GM 3 wire pressure switch for the AC. They make mention of it in the harness manual but they don't say where to look, or what it looks like, only that if you don't have one they can help integrate it.
Old 07-14-2015, 07:42 AM
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Low speed should come on at 209 and off at 199 and on high 229 off at 199...at least that's how mine are tuned
Old 07-14-2015, 09:37 AM
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Guys, thanks for the help, I talked to the tuner today and got it sorted out hopefully.
Old 07-14-2015, 10:49 AM
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To test the harness ground the two wires you put in the pcm manually. Grounding the low speed one should make both fans come on low, ground both should make both come on high.
Old 07-14-2015, 11:30 AM
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Turn on on ignition...fudge it.
Old 07-14-2015, 03:48 PM
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Originally Posted by Randy 5.3
Turn on on ignition...fudge it.
Umm huh?

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