MGB-GT blowing fuzes

[Sopwith_Camel]

well heavy rain today and on my way into work the windshield wipers blew the Fuse. i popped in a new one and it blew as soon as i started the car.
ok is it time for a new moter? or is it water some where where it shouldnt be? or some thing else??

steve

 

[YakkoWarner]

It may not be the motor. The linkages might be stuck/jammed - if the motor is trying to turn and cannot for some reason, it would cause an excess current draw and a blown fuse. Its a pain to get to behind the dash, but if you can take the cover off the motor/gear assembly and disconnect the linkage from the motor, you should be able to move the linkage and wipers freely by hand. If you can't (and if the motor runs freely when not on the linkages) than something mechanical is stuck. If the motor still runs poorly or blows fuses, then its probably the problem.

 

[Sopwith_Camel]

ahhh , maybe the new wiperblades caused too much friction.
I had the moter apart about 4 years ago when i swaped from RHD, to LHD.

 

[JPSmit]

that should be easy enough to check - turn up the wipers (or pop them off)

 

[Sopwith_Camel]

ouch ok in a break in the rain, i put up the wipers and no luck.

 

[JPSmit]

I am inclined to think there is water where it shouldn't be - if they were working ... they typically stop from lack of use.

 

[Sopwith_Camel]

well i have been in the roadster all summer, so the GT has been idle. I havent checked the Switch yet. I think that should be next.
I will take the roadster to work tomarrow

 

[Sopwith_Camel]

well, it dose not seem to be the switch, and it has stopped blowing fuses .
I did get it to run briefly after playing with the input wires to the motor. with the blades off the glass. an hour later i tried testing it again no life.

 

[Sopwith_Camel]

ok the wiper motor runs when out of the car on the bench.

 

[JPSmit]

ok the wiper motor runs when out of the car on the bench.

well duh, leave it on the bench then

Seriously, good news in that it isn't the motor.

On the Midget the motor is easy-ish to remove - the actual wiper mechanism is not - so, assuming the mechanism is still on the car is it free? Is it binding anywhere?

If not then basically we are talking about the wiring - which is fuse - switch / switch - motor / and connectors. My money is on either a connector or a random wire that has rubbed through and is grounding on something.

progress

 

[Sopwith_Camel]

this is on my B GT, yeah the moter gave a small fight but was fairly easy to pull out and put back and i cleaned up the connectors.
the wipers seem to move freely when I move the cable.
ok running new wires, there gose sunday.

 

[Sopwith_Camel]

ok, i checked the wires from the switch and they are good. the wire from the fuse box to the switch is good and i have cleaned up the grounds.

could it be a weak ground back at the battery?

 

[YakkoWarner]

A weak ground usually just results in poor running because of insufficient current flow. Not sure how that could cause an overcurrent situation which is what blows fuses.

If you are certain that the motor and all the wiring going to it is up to par, I'd start investigating what else is on the same fused circuit as the motor, and see if you have a marginal/intermittant current draw elsewhere that may not be enough to blow a fuse on its own but combined with the wiper motor hits/exceeds the limit and pops the fuse. Unfortunately with only 4 fuses, nothing is on its own circruit and that makes tracking things down more of a challange.

 

[JPSmit]

Have you opened the motor and regreased it? dried grease normally only slows the wipers down but, it might be jamming something but typically wiper motrs are pretty nasty inside

 

[Sopwith_Camel]

well i found one issue the extra in line fuse holder was faulty. but then the question is what caused it to start blowing 30a fuses in the rain?
i filled the back of the little wire block with silocon to keep water out.