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PWB

‘67 rear defrost inop

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So my stock rear window fan just decided to quit. 

Strange. I wasn’t using it to burn it out.

All the wires to the motor and switch are undisturbed. But I don’t see a fuse anywhere. Is there one?

 

 Thanks 

Paul

 

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So, there's no power at the motor?  How 'bout the switch?

Edited by EmTee (see edit history)
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The RR defroster is probably one of the least used options. The switches tend to not work from lack of use. They can be taken apart carefully and cleaned. The motor tends to not work from lack of use. Also can be taken apart and lubed/cleaned. Fuse is off the reverse lights and turn signals. Low speed uses a resistance wire. Check for 12V at motor with switch on high. If none go to switch. And check shop manual page 120-128!

 

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2 hours ago, JZRIV said:

The RR defroster is probably one of the least used options.

 

Well, Goldie doesn't have one, so this one issue I won't need to worry about!  :P  On the other hand, since I've used the one in my GP exactly zero times since I've owned it I'll have to give it a try next time I'm in the garage...  ;)

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16 hours ago, EmTee said:

 

Well, Goldie doesn't have one, so this one issue I won't need to worry about!  :P  On the other hand, since I've used the one in my GP exactly zero times since I've owned it I'll have to give it a try next time I'm in the garage...  ;)

LoL 

 

I'm like a kid in the toy store every time I drive the Riv.

Gotta play with everything.

Never gets old, eh?

 

I'm still itchin for a loaded boat tail...but the prices are absurd these days.

 

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On 8/16/2019 at 12:36 PM, PWB said:

Gotta play with everything.

Never gets old, eh?

 

Ha - well, as I said the other day I went out and flipped the defog switch on the GP today and...

 

...Nothing.

 

Soooo, I got my test light and sure enuf there was voltage at the motor on both Hi and Low.  I smacked it a couple of times with the handle of a screwdriver, to no avail.  Next I took the motor down from the package tray and tried turning the fan, but found the motor stuck.  I removed the fan, sprayed some WD-40 at the upper shaft bushing and was able to turn the shaft with a wrench on the fan nut.  It freed-up pretty quickly after that and I put a few drops of oil on the upper shaft bushing, spun it by hand, then brought it over to a spare boat battery and ran it a few seconds.  A couple more drops of oil and I ran it again on the battery.  I put it back together and back into the car.  The good news is it now works but -- it sure makes a racket back there, especially on high speed.  It's easy to see why the embedded resistance grid defrosters replaced the old blower motor units.

 

So, if you already haven't done so, I'll bet you have the exact same issue with the defogger motor on your Riviera.  If so, it's an easy fix.  Just remember to flip the switch every so often to keep the motor from sticking again!  ;)

Edited by EmTee
typo (see edit history)
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8 hours ago, EmTee said:

so, it's an easy fix.  Just remember to flip the switch every so often to keep the motor from sticking again!  ;)

EmTee, I’ve got to let curiosity go on hold in some repair cases. I truly want to fix stuff the correct way. Sometimes I second guess myself and fix it until it is broke. 

Turjinator

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2 hours ago, Turbinator said:

I truly want to fix stuff the correct way.

 

I hear you and concur.  The situation in this case, however, appears to be that condensation and lack of use caused the motor shaft to 'stick' to the upper bushing.  The entire blower assembly looked as new - the bushing was tight (no slop in the shaft) .  I thought about drilling a small hole to allow oiling the bottom bushing, but once the upper bushing became unstuck, the shaft spun freely.  I really think the root cause was galvanic action between the upper bushing and shaft due to lack of use.  I plan to flip the switch every so often from now on, so we'll see what happens...

Edited by EmTee (see edit history)

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7 hours ago, EmTee said:

 

I hear you and concur.  The situation in this case, however, appears to be that condensation and lack of use caused the motor shaft to 'stick' to the upper bushing.  The entire blower assembly looked as new - the bushing was tight (no slop in the shaft) .  I thought about drilling a small hole to allow oiling the bottom bushing, but once the upper bushing became unstuck, the shaft spun freely.  I really think the root cause was galvanic action between the upper bushing and shaft due to lack of use.  I plan to flip the switch every so often from now on, so we'll see what happens...

Your skill in trouble shooting and diagnostics are sharp. The older I get I figure if I clean all the gunk out and check out all the connections as clean and tight I have a chance the thing might work. I just put on a new severe duty clutch fan in hopes of improving my AC performance while in traffic back ups. I couldn’t get the new fan to fit on the existing shaft. I measured the shaft and the receiver end and they were way out. By accident I knocked the bushing off the shaft and the new severe duty clutch fan went right on! I call that, “ blind squirrel finds an acorn”. BTW, Tom Telesco’s recommendation to use the severe duty clutch fan has improved AC performance.

Turbinator

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1 hour ago, Turbinator said:

The older I get I figure if I clean all the gunk out and check out all the connections as clean and tight I have a chance the thing might work. 

Turbinator

Are you talking about your car or my gastro-intestinal tract?

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On ‎8‎/‎16‎/‎2019 at 9:36 AM, PWB said:

Gotta play with everything.

Never gets old, eh?

 

We don't need to hear about your shower habits. ;) 

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It looks like I'm in the minority, as I use mine on a regular basis.  Of course, it depends much on where you live, as the need depends on the weather.  Cold winters and damp springs are when it's most useful.  It also helps to have your cabin nice and toasty as well, as it draws air from inside rather than from the trunk as some think.  This is one reason I rewired the defroster to use the maximum blower output; it moves hot air to the rear much more quickly.  It could be aimed a little better and have more complete coverage, but it will make a clear spot on the window fairly quickly.

 

The defroster itself shouldn't be any noisier than a bathroom exhaust fan or the HVAC blower.  If it's lubed and tight and the fan blades are straight, it's fairly quiet.

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