Always getting error codes about the fan relays

[sttubs]

2003 Impala 3.8L, has 155,000 on it. I keep getting check engine lights with an error code about the fan relays. I've replaced them and reset the computer and a few days later it will throw another code. Sure enough the relay is shot and only one fan works replaced it again and same thing happens a few days later. I didn't know if this is a common problem or can the relay block be replaced or other ideas?

[55trucker]

You're seeing the result of the problem, not the source of the issue.

 

The relay failing is caused more than likely by a short in either the control side or the switch side of the circuits, there may be a poor ground somewhere which is causing a large amount of current draw thru the circuit.

The relays are 30 amp items, to fail it would have to get on the hot side.

 

When the relay fails, the fans do not engage  & a code is set.

 

are you seeing P0480,481 or 485?

[Schurkey]

In MY driveway, those fans would be tested for current draw with a clamp-on probe 'n' a multimeter.

 

Wild Guess:  Failed fan motor(s) pulling so much current the relay gets cooked.

 

Of course, shitty Chinese relays could be under-engineered, too.

[sttubs]

Thanks for the input guys. It usually is fan #2 relay so fan motor may be it. I won't be able to check things out till the weekend though.

Schurkey I'm not sure what you mean by clamp on probe, could you please link me to what product you are talking about. TIA

[Imp558]

 

He means a tool like this to test current draw. Fan 2 doesn't get used much and they are often less than healthy so you may be on to something.

 

 

https://m.lowes.com/pd/Extech-Digital-Clamp-Meter/999990686?cm_mmc=SCE_PLA_ONLY-_-ToolsAndHardware-_-SosHandTools-_-999990686:Extech&CAWELAID=&kpid=999990686&CAGPSPN=pla&k_clickID=cb8711ee-06e1-4311-be3f-5ef47dca553a&gclid=CjwKCAiA0IXQBRA2EiwAMODil5iT0KUMWk4X5vN679liAuX_7hKrmRaEH53irMF0imZNVv3i4ci1uxoCQssQAvD_BwE

[White93z34]

Just try and spin the fan by hand. that alone may be an indicator.

 

How hot do the relays get under operation? they shouldn't get hot at all.

[Schurkey]

I got mine here, although I think I bought the "house brand" version of the one pictured.  I also got mine with a conversion harness so I have typical multimeter banana jacks instead of just the BNC connector.  This one reads from 10 milliamps to 60 amps, pretty-much covers everything automotive except for starting/charging/battery testing--and I have a dedicated starter/alternator/battery tester for that.  Also does AC testing along with DC.

 

https://www.aeswave.com/Current-Clamp-60A-AC-DC-with-BNC-p9417.html

 

You want to know both the amperage the device is drawing, along with the voltage the circuit supplies.

 

The amp probe connects to a multimeter to display amperage readings.  Does not require disconnecting the device you're testing--you just clamp the probe around the power wire.

 

Ideally, this is used with an oscilloscope rather than a multimeter.  The oscilloscope can provide a display of the current draw for EACH INDIVIDUAL ARMATURE BAR of an electric motor, and allows you to calculate the RPM of the motor as it runs.  If the overall amperage of the motor is acceptable, AND each armature bar draws the same amount of current, AND the RPM is good...the motor is probably good.  If one or more armature bars has an unusual current draw (too much or too little) or the RPM is low, the motor may be bad.