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#2588526 - 12/07/18 09:18 AM Blower fuse overheating
RapidusMaximus Offline
top fuel

Registered: 06/04/03
Posts: 2012
Loc: Haslet, Texas
This seems to be a common problem on mid 70s Dodges...is there a common problem/cure. I've already changed the blower motor. This happens to be on a 74 truck but I've seen it occur on others also? 20amp fuse gets extremely hot but doesn't blow out?


Attachments
20181207_080701-1.jpg


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1968 Plymouth GTX 440 4 Speed Dana
1967 Small block Dart under construction
1974 Dodge P/U Long Bed Stepside 318 Auto
1975 Jeep CJ5
1994 Turbocharged Fuel Injected Dakota (for sale or trade)
2016 Dodge Ram Hemi 1500

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#2588528 - 12/07/18 09:21 AM Re: Blower fuse overheating [Re: RapidusMaximus]
dvw Offline
master

Registered: 03/16/06
Posts: 7303
Loc: MI, usa
Check if the fuse holder is rusty at the fuse or around the rivet holding it. Also check the connectors at the switch and under at the heater case. Poor connection leads to high resistance drawing more amperage. Amperage creates heat.They may be melted as well.
Doug

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#2588557 - 12/07/18 10:25 AM Re: Blower fuse overheating [Re: RapidusMaximus]
JS Restorations Offline
enthusiast

Registered: 01/13/08
Posts: 370
Loc: Pittsburgh, PA
I agree with dvw.

This 2820408 A body convertible switch arrived yesterday for restoration and is exhibiting a similar and typical cause of this failure. The center rivet had become slightly loose from the pressure of the outboard circuit breaker movement. Pictures 3 and 4 do show the left to right movement that is occurring.

The effect of this slight arcing between the center connecting blade from the circuit breaker and the rivet, builds up heat and is what takes the hit on the internal return knob centering isolation pin melting. The knob then is unable to apply pressure on the internal swing arm for up or down movement.











Jim
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#2588584 - 12/07/18 10:59 AM Re: Blower fuse overheating [Re: dvw]
rustbuckett68 Offline
mopar

Registered: 06/17/06
Posts: 596
Loc: Alberta
The connector thing happened on my '79 van. Turned out to be a bad plug to the heater motor located under the glove box liner. Replaced it and it worked so well I put the original heater motor back in. How a connector in the interior corroded is anyone's guess, but that's electronics for you.

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#2588594 - 12/07/18 11:11 AM Re: Blower fuse overheating [Re: rustbuckett68]
RapidusMaximus Offline
top fuel

Registered: 06/04/03
Posts: 2012
Loc: Haslet, Texas
Thanks for the input guys, been laying under the dash checking wires and connections, pulled the glove box liner and was able to disconnect this from the bottom of the melted fuse location, the other connection looks about the same but is part of a "bar" and not removable...could this be it?


Attachments
20181207_100434-1.jpg

20181207_100447-1.jpg


_________________________
1968 Plymouth GTX 440 4 Speed Dana
1967 Small block Dart under construction
1974 Dodge P/U Long Bed Stepside 318 Auto
1975 Jeep CJ5
1994 Turbocharged Fuel Injected Dakota (for sale or trade)
2016 Dodge Ram Hemi 1500

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#2588600 - 12/07/18 11:20 AM Re: Blower fuse overheating [Re: RapidusMaximus]
JS Restorations Offline
enthusiast

Registered: 01/13/08
Posts: 370
Loc: Pittsburgh, PA
If you can twist the fuse holder blade section while holding the male terminal behind it and it slightly turns, you found the problem. That rivet will need tightened, after cleaning.

Jim
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#2588607 - 12/07/18 11:27 AM Re: Blower fuse overheating [Re: JS Restorations]
RapidusMaximus Offline
top fuel

Registered: 06/04/03
Posts: 2012
Loc: Haslet, Texas
It's tight but corroded and as a side note this came from the melted side which is also the ground side. May not mean anything but it shows continuity from end to end.
_________________________
1968 Plymouth GTX 440 4 Speed Dana
1967 Small block Dart under construction
1974 Dodge P/U Long Bed Stepside 318 Auto
1975 Jeep CJ5
1994 Turbocharged Fuel Injected Dakota (for sale or trade)
2016 Dodge Ram Hemi 1500

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#2588608 - 12/07/18 11:28 AM Re: Blower fuse overheating [Re: RapidusMaximus]
RapidRobert Offline
Circle Track

Registered: 11/20/03
Posts: 34405
Loc: Lincoln Nebraska
Quote:
could this be it?
As said yes. A HF $9.99 dremel tool/kit works perfect for getting the inside of those tangs to bare metal. In addition there may be poor continuity in the crimp/rivet of that fitting but for a good start I would dremel it & hook it up under the hood with some jumpers from battery to fuse terminal to blower & run it & see if that terminal assy all stays cool by hotwiring the blower for several minutes. EDIT then if all good, reinstall it in the fuse holder box in the pic.


Edited by RapidRobert (12/07/18 11:35 AM)
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#2588622 - 12/07/18 12:06 PM Re: Blower fuse overheating [Re: RapidusMaximus]
Supercuda Offline
I Live Here

Registered: 09/04/07
Posts: 14098
Loc: up yours
Rusty connections are poor conductors and can cause your issue.
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#2588656 - 12/07/18 01:20 PM Re: Blower fuse overheating [Re: Supercuda]
moparx Offline
Dreaming of implants

Registered: 09/03/03
Posts: 9732
Loc: north of coder
Originally Posted By Supercuda
Rusty connections are poor conductors and can, and WILL, [fixed it for ya] cause your issue.



^^^^^^ right on the money here ! iagree and has been said many, many times, grounds are VERY IMPORTANT to keep your electrical system working properly !
beer

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#2588688 - 12/07/18 02:38 PM Re: Blower fuse overheating [Re: RapidusMaximus]
therocks Offline
Its Lost

Registered: 01/20/03
Posts: 19465
Loc: Niles , Ohio
They had problems with the blower speed switch also.I replaced quite a few when I had my Rams.Rocky
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#2588714 - 12/07/18 03:37 PM Re: Blower fuse overheating [Re: therocks]
RapidusMaximus Offline
top fuel

Registered: 06/04/03
Posts: 2012
Loc: Haslet, Texas
Well, after a couple hours standing on my head...ugh...under the dash looks like a lot of the wiring has been "warm", gotta love these old vehicles, guess I'll just take it wire by wire, plug by plug. The three way switch may be a good call, it's plug in's are cracked and broken and mechanically it isn't very smooth. Thanks for everyone's input, I'll keep plugging along work
_________________________
1968 Plymouth GTX 440 4 Speed Dana
1967 Small block Dart under construction
1974 Dodge P/U Long Bed Stepside 318 Auto
1975 Jeep CJ5
1994 Turbocharged Fuel Injected Dakota (for sale or trade)
2016 Dodge Ram Hemi 1500

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#2588807 - 12/07/18 07:06 PM Re: Blower fuse overheating [Re: RapidusMaximus]
TJP Offline
master

Registered: 01/24/03
Posts: 8581
Loc: Omaha Ne
Originally Posted By RapidusMaximus
It's tight but corroded and as a side note this came from the melted side which is also the ground side. May not mean anything but it shows continuity from end to end.


Continuity at zero current is one thing, the ability to pass current is another. The higher the draw (current wise) the more critical connections and contacts become.Those fuse box connections are TOASTED (No pun intended)

beer
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#2589508 - 12/09/18 03:53 PM Re: Blower fuse overheating [Re: TJP]
RapidusMaximus Offline
top fuel

Registered: 06/04/03
Posts: 2012
Loc: Haslet, Texas
Update: thanks to everyone's suggestions and input, disassembled and cleaned every connection I could, including the grounds, put it all back together and now the fan blows on all three speeds without warming the fuse...sweet...but what a pain, lol laugh2 up
_________________________
1968 Plymouth GTX 440 4 Speed Dana
1967 Small block Dart under construction
1974 Dodge P/U Long Bed Stepside 318 Auto
1975 Jeep CJ5
1994 Turbocharged Fuel Injected Dakota (for sale or trade)
2016 Dodge Ram Hemi 1500

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#2589527 - 12/09/18 04:39 PM Re: Blower fuse overheating [Re: RapidusMaximus]
bboogieart Offline
master

Registered: 01/12/08
Posts: 3630
Loc: Lost and Spaced
Glad you got it sorted.


Got some wiring to do myself this winter.
At least I have the seats out of the way.
Werkin upside down under the dash aint quite what I consider fun.
Nice once you get it done though.
smile
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#2589652 - 12/09/18 09:12 PM Re: Blower fuse overheating [Re: bboogieart]
RapidusMaximus Offline
top fuel

Registered: 06/04/03
Posts: 2012
Loc: Haslet, Texas
Originally Posted By bboogieart
Glad you got it sorted.


Got some wiring to do myself this winter.
At least I have the seats out of the way.
Werkin upside down under the dash aint quite what I consider fun.
Nice once you get it done though.
smile

Thanks! Yes, working under the dash is no fun wrench runaway
_________________________
1968 Plymouth GTX 440 4 Speed Dana
1967 Small block Dart under construction
1974 Dodge P/U Long Bed Stepside 318 Auto
1975 Jeep CJ5
1994 Turbocharged Fuel Injected Dakota (for sale or trade)
2016 Dodge Ram Hemi 1500

Top
#2589836 - 12/10/18 11:46 AM Re: Blower fuse overheating [Re: RapidusMaximus]
moparx Offline
Dreaming of implants

Registered: 09/03/03
Posts: 9732
Loc: north of coder
thanks for the update, and glad you got it sorted out !
beer

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