A/C clutch fuse keeps blowing after high speed radiator fan kicks in.

A

atikovi

Joined
Apr 27, 2010
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Just fixed the leaking a/c line oring on this 2003 Honda Insight but have another problem. When the a/c is turned on the compressor clutch engages, the condenser fan comes on and the radiator fan comes on low speed like it’s supposed to. The clutch and condenser fan are on the same 20 amp fuse #19. The radiator fan is on fuse #11. After about a minute, the radiator fan kicks into high speed and then fuse #19 blows. Here is the wiring diagram,

wiring.jpg


The compressor clutch alone draws 3.5 amps off the 20 amp fuse #19 when jumped at the relay.

I jumped the condenser fan relay connector terminals 1&2. Then I jumped the fan control relay connector terminals 1&4 which makes both the condenser fan and radiator fans run at low speed off the 20 amp fuse #19. That draws about 5 amps at first and then settles down to 3.7 amps.

Next, at the fan control relay, I changed the 1&4 jumper to 1&2 which runs the condenser fan only. That initially draws 17 amps which drops down to 12-15 amps in a few seconds. Is this the problem? The 17 amp draw of that fan combined with 3.5 amp from the clutch coil blows the fuse? The condenser fan is drawing too much current and is bad?

What I don't get it why the two fans together only draw 3.7 amps but the condenser fan alone draws so much more? That doesn't make sense.
 
atikovi said:
What I don't get it why the two fans together only draw 3.7 amps but the condenser fan alone draws so much more? That doesn't make sense.
Click to expand...
What you're missing is that when the fan relay switch closes contacts 1 to 4, battery voltage is going to be split between the condenser fan motor and the radiator fan motor, which are now connected in series, causing both motors to run at reduced speed and load, hence the low current reading.

When the rad fan kicks into high speed, this also provides the condenser fan with full voltage and load at the same time, and it's the inrush current from the condenser fan causing the 20A fuse to blow.

You may not be using the proper type of fuse. A 20A time-delay fuse will allow for more inrush current than a standard fuse while still protecting the motors and wiring. Even if Honda doesn't specify a time-delay fuse, I would try one out. Stick with the 20A rating.

It sounds like the total continuous load on the 20A fuse is 15.5 A to 18.5 A. Normally a fuse is rated to carry 80% of its rating continuously to provide some margin, or 16 A in this case. If the measured current is averaging over 16 A, chances are the condenser fan is drawing a bit more current than the designers intended, but I wouldn't rush to replace it at this point. Try a new fuse first.

Edit: Should have read your last post. It does sound like the condenser fan is bad.
 
Would it be possible to take the fan motor apart, clean it up, install new brushes if needed, grease the bearings (or install new ones), and put it back together?
 
chemman said:
Would it be possible to take the fan motor apart, clean it up, install new brushes if needed, grease the bearings (or install new ones), and put it back together?
Click to expand...
I don't think that would be possible. These aren't made to be repairable.

IMG_7524.JPG


IMG_7527.JPG


I should have one off a parts car I can use.
 
twX said:
What you're missing is that when the fan relay switch closes contacts 1 to 4, battery voltage is going to be split between the condenser fan motor and the radiator fan motor, which are now connected in series, causing both motors to run at reduced speed and load, hence the low current reading.

When the rad fan kicks into high speed, this also provides the condenser fan with full voltage and load at the same time, and it's the inrush current from the condenser fan causing the 20A fuse to blow.

You may not be using the proper type of fuse. A 20A time-delay fuse will allow for more inrush current than a standard fuse while still protecting the motors and wiring. Even if Honda doesn't specify a time-delay fuse, I would try one out. Stick with the 20A rating.

It sounds like the total continuous load on the 20A fuse is 15.5 A to 18.5 A. Normally a fuse is rated to carry 80% of its rating continuously to provide some margin, or 16 A in this case. If the measured current is averaging over 16 A, chances are the condenser fan is drawing a bit more current than the designers intended, but I wouldn't rush to replace it at this point. Try a new fuse first.

Edit: Should have read your last post. It does sound like the condenser fan is bad.
Click to expand...
The radiator fan gets power from 2 relays: the radiator fan relay and the AC condenser fan relay. Why? I'm not sure.
 
atikovi said:
Discontinued

Air Conditioner (Condenser) for 2001 Honda Insight | Honda Parts Online

www.hondapartsonline.net www.hondapartsonline.net
Click to expand...

80151-S3Y-003 - Genuine Honda Motor, Cooling Fan

HondaPartsNow.com offers the great deal for genuine Honda parts, 80151S3Y003. Motor, Cooling Fan for $204.77. All parts are backed by the Honda's warranty.
www.hondapartsnow.com www.hondapartsnow.com

80151-S3Y-003 - Motor, Honda OEM | Megazip.net

80151-S3Y-003 - Motor, Honda. New spare parts Honda from Japan with easy payment system and door-to-door delivery.
www.megazip.net www.megazip.net

It's probably discontinued, but place the order and see what they say 🤷‍♂️
 
I tried that for another part that showed available, from a place in Saudi Arabia, and 3 days later was refunded. If it says discontinued it means NLA.
 
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