Wipers blow fuse only on low setting?

[lyrikz]

:UPDATE:
So i might have figured out the issue. What size fuse should be in the wiper motor location? Anyone know?


Finally getting the truck 100%. Adding the final things like wipers and what not. The wipers have sat for 4 years. I lubed everything up and turn on the wipers. They do about 2 swipes and then pop the fuse. LIttle more lube and they do about 3 swipes and pop the fuse. Heres the thing, it ONLY pops the fuse when they are on the lowest setting. If i click it to the 2nd or third setting they stay on fine.

71 chevy pu.

Thoughts?

[eurospec1]

Originally Posted by lyrikz

Finally getting the truck 100%. Adding the final things like wipers and what not. The wipers have sat for 4 years. I lubed everything up and turn on the wipers. They do about 2 swipes and then pop the fuse. LIttle more lube and they do about 3 swipes and pop the fuse. Heres the thing, it ONLY pops the fuse when they are on the lowest setting. If i click it to the 2nd or third setting they stay on fine.

71 chevy pu.

Thoughts?

Wire shorted on the low side between your switch and the motor would be my guess

[alsriv2]

Might possibly be a defective switch. If the low position is worn, it could provide a path to a ground causing the failure.

Al
'69 Gmc 2500 Custom Camper
'69 Chevy C10 396

[lyrikz]

Originally Posted by alsriv2

Might possibly be a defective switch. If the low position is worn, it could provide a path to a ground causing the failure.

Al
'69 Gmc 2500 Custom Camper
'69 Chevy C10 396

Wire shorted in the motor internally???

[alsriv2]

Originally Posted by lyrikz

Wire shorted in the motor internally???

I was thinking the dashboard turn switch itself. I once had a '67 that one of the positions would not operate the wipers at all. I replaced the dash switch and problem solved.

Al

[davepl]

Well, I'm not certain how the switch controls speed, but if it uses a resistor to limit current for the low speed, and that resistor was shorted, then it would blow the fuse on LOW but cause no problem on HIGH. Just a guess.

Use an ohmmeter to measure the resistance from input to the output(s) when the switch is off, low, and high. Should be infinite, some number, and zero. If it's zero in both low and high, that's your short I would imagine.

[lyrikz]

Originally Posted by davepl

Well, I'm not certain how the switch controls speed, but if it uses a resistor to limit current for the low speed, and that resistor was shorted, then it would blow the fuse on LOW but cause no problem on HIGH. Just a guess.

Use an ohmmeter to measure the resistance from input to the output(s) when the switch is off, low, and high. Should be infinite, some number, and zero. If it's zero in both low and high, that's your short I would imagine.

They have resistors back on those old things?

[D.PASSMORE]

Thought: make sure the wiper arms are moving freely. Way back when, I remember that my wiper arm studs were corroded up and were hard to turn. I went through a few motors before i figured it out. R&R'd them and never had another problem.

[lyrikz]

Originally Posted by D.PASSMORE

Thought: make sure the wiper arms are moving freely. Way back when, I remember that my wiper arm studs were corroded up and were hard to turn. I went through a few motors before i figured it out. R&R'd them and never had another problem.

Possible, but they move pretty free on a higher setting and they move free on the lower setting...

Hmmm. On the washer switch there is three wires. ground, power to squirter and power to wiper motor. So there has to be a resistor in there somwhere

[schurg]

I'm pretty sure the switch controls the ground side of the wiper motor. the power goes from the fuse panel straight to the motor assembly... I'd say there is an issue in the wiper assembly itself.

[davepl]

Yes, they use resistors, but they're probably integral to the motor, not in the switch, if for no other reason than getting rid of the heat... note that the hi/lo heater fan switch has to use a big external resistor in the airflow path.

In any event, I believe the wiper switch provides two different paths to ground. The power wire at the motor is hot with ignition, and low grounds part of the internal resistor network and high grounds both parts.

That said, I was wrong in my original post - and agree it's pretty much got to be a fault in the motor, not the switch. You could still use the ohmmeter to confirm it, but you'd have to do it at the wiper motog connectors.

[lyrikz]

Originally Posted by schurg

I'm pretty sure the switch controls the ground side of the wiper motor. the power goes from the fuse panel straight to the motor assembly... I'd say there is an issue in the wiper assembly itself.

I may have figured out my problem. I replaced all my fuses, or removed them. Well, i think i put the wrong fuse in. What size fuse should be in the wiper motor location?

[D.PASSMORE]

Originally Posted by lyrikz

Possible, but they move pretty free on a higher setting and they move free on the lower setting...

I thought so too, until I physically tried to move them.
Popped a few fuses, fried the motors after awhile...
Good luck.

[va72longhorn]

Its more of a current draw issue than it is a short issue. If it was a direct short, you wouldnt get two swipes of the wipers before it blows. If the linkages and joints are rusted or gumed up this will create more of a current (amperage) draw than normal. Its not quite as bad in the higher speeds because its getting " a running start". Kinda like pushing a truck with the tires half flat, it takes more energy, but once it gets going it aint bad. Putting a larger fuse in will only buy you time. Take the arms off and make sure everything is lubricated good. Use some penertrating oil (WD40, Blast, etc) on the all the linkages and then run the wipers with out the arms on them for a couple of minutes. Then stick the arms back on. After sitting for four years, theres nothing to lose.

[lyrikz]

Originally Posted by va72longhorn

Its more of a current draw issue than it is a short issue. If it was a direct short, you wouldnt get two swipes of the wipers before it blows. If the linkages and joints are rusted or gumed up this will create more of a current (amperage) draw than normal. Its not quite as bad in the higher speeds because its getting " a running start". Kinda like pushing a truck with the tires half flat, it takes more energy, but once it gets going it aint bad. Putting a larger fuse in will only buy you time. Take the arms off and make sure everything is lubricated good. Use some penertrating oil (WD40, Blast, etc) on the all the linkages and then run the wipers with out the arms on them for a couple of minutes. Then stick the arms back on. After sitting for four years, theres nothing to lose.

LOL, no one is reading my other posts. The fuse is the wrong size. I have a 3 amp fuse in there. 3. The fuse that should be in there is 25 amp i believe. I just was hoping someone could go out to their truck and tell me what the correct size is for the wiper fuse. I cant find a stock diagram or anything like that.

[davepl]

According to my owner's manual the wiper fused is supposed to be 20 AGC. My lawyer won't let me say you can run a 25, but I'd imagine that's ok too.

I bet it'd pop a 3 amp fuse pretty quick! I'm surprised it would surive on high either.

[john]

here you go.

[lyrikz]

Originally Posted by davepl

According to my owner's manual the wiper fused is supposed to be 20 AGC. My lawyer won't let me say you can run a 25, but I'd imagine that's ok too.

I bet it'd pop a 3 amp fuse pretty quick! I'm surprised it would surive on high either.

Sweet, 20 it is. Im suprised to.. But this fuse is wire thin.. Then i saw some pics of other wiper fuses and was like WOOOAH thats way wrong... I believe i put that small ass fuse in EVERY fuse location so when i put power to everything the first time, nothing would blow. Well, nothing did blow except for the wiper motor.

[lyrikz]

Originally Posted by john

here you go.

OMG im such an idiot.. IT SAYS IT RIGHT ON THE FUSE PANEL. lol. Wow.
Talk about overlooking something...

Sorry for wasting all your guys time.

[va72longhorn]

Yeah, Im very surprised that it ran at all on a 3 amp.

[D.PASSMORE]

I believe a 20 Amp

[lyrikz]

Originally Posted by va72longhorn

Yeah, Im very surprised that it ran at all on a 3 amp.

Yep, ran all day on high. Low it would pop it.

[lil hoodlum]

Originally Posted by lyrikz

OMG im such an idiot.. IT SAYS IT RIGHT ON THE FUSE PANEL. lol. Wow.
Talk about overlooking something...

Sorry for wasting all your guys time.

LOL!

We all have those moments!

Keith

[lyrikz]

Originally Posted by lil hoodlum

LOL!

We all have those moments!

Keith

I was searching all over the internet for this info. Looking at those fuse panels and just did not see the 20 amp right there on it...

Sigh... oh well.