Blowing fuses

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Fatrover

Fatrover

Well-Known Member
Posts
941
Location
Argyll, Scotland
replaced the wiper motor on my 76 ser 3 and when i turn it on, it immediately blows a fuse. Have taken it off the wheelbox and tried it and the same happens. When i first installed it, it worked fine for a short time. Puzzled beyond belief.
 
Why did you replace it ? Have a look at the loom near the wiper motor and at the switch end. Try switching it without connecting the wiper motor. A previous overload may have cause some melting
 
Yes its def had an overload, the old wheelboxes seized which caused the motor to fry. It seems to be trying to pull a lot of power which is causing the fusing. Wiring isnt ,my strong point at all....it looks pretty ropey to be fair
 
Fatrover said:
Yes its def had an overload, the old wheelboxes seized which caused the motor to fry. It seems to be trying to pull a lot of power which is causing the fusing. Wiring isnt ,my strong point at all....it looks pretty ropey to be fair
Click to expand...
Has the motor seized?
 
Ive tested the motor, its fine, oddly enough before it started blowing fuses it was going with the switch in all positions and the key out of the ignition, only way to stop it was to disconnect it. Wiring i think...
 
Park switch. Its a 2-way switch, and is always live, that's why you can't stop the wipers if it fails. Other contact is earth becuse it earths the motor to stop it otherwise the momentum carries it acors the park detent. It can short the life side to earth. The wiper on/off swich should be wired to by-pass the park switch. The dash swich positions are actually "run" and "run to park" not off.
 
rob1miles said:
Park switch. Its a 2-way switch, and is always live, that's why you can't stop the wipers if it fails. Other contact is earth becuse it earths the motor to stop it otherwise the momentum carries it acors the park detent. It can short the life side to earth. The wiper on/off swich should be wired to by-pass the park switch. The dash swich positions are actually "run" and "run to park" not off.
Click to expand...

Right, got that. The motor and park switch are new. The dash switch has three positions, its a Lucas one. Nightmarish....
 
This is the circuit. The 12 supply goes to the dash switch and is always on (it should come off the "ign" terminal so its off when you turn the key off) the connections are to run the motor via the park switch (run to park) or by pass the park switch (run). You need to work out the pins on the lucas switch: The park switch is your enemy, it has live and earth and these must never be switched together, it must be one or the other. Same with dash switch, one side is live but the other switches to the park switch which switches to earth. If you get dead shorts stop and go over the connetions again as odds on one is connected wrong. 3 pos switch could be 2 speed wiper. In this case there are 2 "run" circuits (fast and slow) but the "run to park" (wiper off) is the same as the pic.
wiper.jpg
 
Thanks Rob, thats a huge help. Doubtless they are all connected wrong. Ill see if theres any wiring damage, hopefully not, and start again!
 
This drawing hopefully has the wire colours ignore the 2nd speed if yours is nor two speed.
 

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