Blower motor testing

[Qumanchew]

Back in spring the fuse for the heater blower started popping. Not right when you turned it on but after a couple minutes running. It's the wild horses upgraded motor and fan. It's not rubbing anything and worked fine for a year or two.

So how do I test the motor? I have it out and it works if you hook it to a battery, but how do I get more in depth than that?

Thanks,John

 

[66CTBronco]

if you have a meter that can measure current that's a start. A clamp-on ammeter, or a volt meter with a "DC AMP" setting that can accomodate 20 amps would work too. fuses fail via melting of the conductive element, and they've got a fairly wide margin: a 10 amp fuse can carry 10 amps continuously. 10.5 amps, probably 10-15 minutes, 10.75 amps probably 15 seconds... so the current may be close. Is it the right size fuse for the motor? is anything else tacked onto this circuit that shouldn't be there to increase the current draw that would cause the fuse to blow? I'm trying to avoid the "increase the fuse size until it doesn't blow" approach lol. That reminds me of Calivn and Hobbes where Calvin asked his dad how they get the weight limit for bridges, and his dad replies "they drive bigger and bigger trucks over the bridge until it collapses, then they weigh the last truck and rebuild the bridge..."
c

 

[Qumanchew]

Haha, exactly what I'm trying to avoid. The wire harness is is Centec that I installed a couple years ago so I know nothing is added to the circuit, so I have that going for me. Fuse size is a good question. I'm pretty sure Centec designated a 20A for the heater and that's what I'm running. In full disclosure, testing of electrical components is a weak point with me. I have a multi meter but that's about it. Thanks for the reply.

John

 

[DirtDonk]

While I also try to avoid the “just turn it up till it melts then back off a notch” method, Broncos used a 20 amp fuse in their original harness, but I believe full-size trucks often used a 25, or even 30 amp fuses in that position.
Not sure what else they might’ve had on that circuit, but early trucks up to 75 or so use the exact same fuse panel we have. 76 and later got a slightly updated 10 position panel.
Seems to me that with an upgraded harness you can do that safely too.

Although it wouldn’t hurt to call Centech just to verify.

 

[Oldtimer]

It's the wild horses upgraded motor and fan. It's not rubbing anything and worked fine for a year or two.
Thanks,John

I would contact WH and ask them for specification on motor, or who makes it for them.