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Relay for heater motor


jesusno2

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The heater is wired directly to 12 volts. The speed switch selects by applying a ground through one or two resistances. More resistance lowers the speed. High speed is simply a direct wire to ground.

 

I found the best thing is a higher output alternator. All alternators have poor output at idle with all the lights and wipers on but a higher output alternator. Instead of idling at 12 volts they are at 14.

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I never noticed much difference in higher amp alternators seem's there isnt much of electrical load on these trucks in stock form. I could see adding higher amp alt if you have like offroad lights alarms stereo etc etc. i would emagine a 60amp alt sould be more than sufficient for that

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They are but need to be revved up more to get full 14.3 volt output. The higher amp ones put this out at much lower RPMs. That's all.

 

A relay is fine if you use much heavier gauge wires so there is less voltage drop. If you use the same wire there's no improvement. As current flow is the same in all parts of a circuit make sure you have a larger ground wire and wires to the switch to carry it.

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Curious also if a relay would help the wiper motor out cause DAMN! You would almost be better off with a hand crank

my wipers move pretty well I thought! But that heater motor when trying to clear the windshield is damn near useless. We've been having more than normal amounts of rain, and I had a fogged up windshield the other day; took ages to clear it. Not sure what you'd do in any actual winter weather with these heaters.

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I have not done this yet, but a 521 all the accessories that are switched off with the ignition are fed through the ignition switch.  There are two black with a white stripe wires on the fuse box.  One is ignition power from the ignition switch, the other goes to the ballast resistor, and coil.  On a stock 521, these two wires are hooked to the fuse box, and supply power to two or three fuses, that supply the heater fan, the wiper motor.

 

Using a Bosch cube type relay, connect the two black with a white stripe wires together, but not to the fuse block.  Run a wire from that connection to pin 86 of the relay.  Ground pin 85.  Connect a fused power source to pin 30 for the relay, and run a wire from pin 87 of the Bosch relay to the place on the fuse block that the black with a white stripe wires were.

 

If you have a heater with a pancake motor, that has a printed circuit armature, you can remove the heater motor from the heater box, and then the back plate of the heater motor can just be pried off, carefully.  Mark it first, there are three locating pins 120 degrees apart.  Clean the surface the brushes ride on, with mineral spirits, and let it dry completely.   Put it back together.  While it is out, carefully clean 45 years of accumulated crud off the heater fan.  I do not recommend trying to remove the nut that holds the squirrel cage to the motor shaft, it is really easy to break the fan.

 

The wiper motor probably will benefit from taking the motor apart, cleaning the 45 year old grease out of it, and putting fresh new grease in the gearbox for wiper motor.

 

 

Almost all modern cars have air conditioning.  When you turn on the defroster, the air conditioning is also turned on, and air is routed through the A/C evaporator.  This cools the air, but also removes a lot of moisture from the air.  That is the main reason modern cars can defog the windows so quickly.

 

It really helps a 521 if you can park it out of the rain, it does not have to be a garage, just something tom prevent rain from falling directly on the truck.  Try to keep the floor dry.  Check the attachment of the defrost ducts under the dash.  Opening a wing window helps suck some air out of the cab when you are moving.  Keep a rag in the cab, to wipe the inside of the windshield.

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I lived with a 521 through 6 Ontario winters not because of the heater.... but in spite of it. The heater core is smaller than the palm of your hand and the fan is just terrible. So improving on terrible will only bring it up to pathetic I'm afraid. Best you can do is get the full 12 volts to the fan and wipers next is a higher output alternator than charges at lower engine speeds and doesn't dim the headlights at stops.

 

I was so cold in it that I removed the glove box and framed up an air conditioner condenser coil and an old '50s heater fan. Plumbed in the hoses to the defrost. It just recirculated cabin air, supplemented by holes in the floor, but boy would it warm the truck up 

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I do not have pictures handy, but earlyvws is replacing the heater in my '69 521 with a Vintage Air hot rod heater unit. I wanted the dehumidified defrost effect that DanielC referred to above.

 

The heater core in this unit is much, much bigger. I dislike listening to heater blower motors, so one benefit is that I should be able to enjoy Africa-hot comfort on cold days in this truck now, and to clear a windshield with no problems. This truck is has turned into a long-term restoration project, but it is almost done. When I get access to pics I'll post some of the install.

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Well here pretty soon im gonna reseal up the heater box (as soon as the core comes back from the raditor shop) with that foam tape from the hardware store. That worked really well on my 510 heater box which seems awfull similar to a 521 heater box defrosters still sucked, but the floor heat was pretty good. I did notice that the trap door on the 521 heater doesnt completely cover the hole for some reason. Seems to me you would want that box sealed up tight to keep it from drawing in any cold air.

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Are you talking about the door controlled by the 'HEAT/SHUT' lever? There is a small set-bolt that help adjust how open that door is. I just adjusted mine. It was open like you describe when the lever was in the SHUT position. Not now.

 

When I rebuilt my heater box I took the motor apart and lubed it up. Works like champ. Defrost still sucks. I think it's the duct design. The air flow isn't directed at the whole windshield.

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