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Blower fuse overheating #2588526
12/07/18 12:18 PM
12/07/18 12:18 PM
Joined: Jun 2003
Posts: 2,083
Haslet, Texas
RapidusMaximus Offline OP
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RapidusMaximus  Offline OP
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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?

20181207_080701-1.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

2016 Dodge Ram Hemi 1500
Re: Blower fuse overheating [Re: RapidusMaximus] #2588528
12/07/18 12:21 PM
12/07/18 12:21 PM
Joined: Mar 2006
Posts: 7,589
MI, usa
dvw Online content
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dvw  Online Content
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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

Re: Blower fuse overheating [Re: RapidusMaximus] #2588557
12/07/18 01:25 PM
12/07/18 01:25 PM
Joined: Jan 2008
Posts: 375
Pittsburgh, PA
JS Restorations Offline
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JS Restorations  Offline
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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

Re: Blower fuse overheating [Re: dvw] #2588584
12/07/18 01:59 PM
12/07/18 01:59 PM
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Posts: 606
Alberta
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rustbuckett68 Offline
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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.

Re: Blower fuse overheating [Re: rustbuckett68] #2588594
12/07/18 02:11 PM
12/07/18 02:11 PM
Joined: Jun 2003
Posts: 2,083
Haslet, Texas
RapidusMaximus Offline OP
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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?

20181207_100434-1.jpg20181207_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

2016 Dodge Ram Hemi 1500
Re: Blower fuse overheating [Re: RapidusMaximus] #2588600
12/07/18 02:20 PM
12/07/18 02:20 PM
Joined: Jan 2008
Posts: 375
Pittsburgh, PA
JS Restorations Offline
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JS Restorations  Offline
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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

Re: Blower fuse overheating [Re: JS Restorations] #2588607
12/07/18 02:27 PM
12/07/18 02:27 PM
Joined: Jun 2003
Posts: 2,083
Haslet, Texas
RapidusMaximus Offline OP
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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

2016 Dodge Ram Hemi 1500
Re: Blower fuse overheating [Re: RapidusMaximus] #2588608
12/07/18 02:28 PM
12/07/18 02:28 PM
Joined: Nov 2003
Posts: 34,995
Lincoln Nebraska
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RapidRobert Offline
Circle Track
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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.

Last edited by RapidRobert; 12/07/18 02:35 PM.

live every 24 hour block of time like it's your last day on earth
Re: Blower fuse overheating [Re: RapidusMaximus] #2588622
12/07/18 03:06 PM
12/07/18 03:06 PM
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Posts: 14,889
up yours
Supercuda Offline
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up yours
Rusty connections are poor conductors and can cause your issue.


They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
Re: Blower fuse overheating [Re: Supercuda] #2588656
12/07/18 04:20 PM
12/07/18 04:20 PM
Joined: Sep 2003
Posts: 10,791
north of coder
moparx Online content
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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

Re: Blower fuse overheating [Re: RapidusMaximus] #2588688
12/07/18 05:38 PM
12/07/18 05:38 PM
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Niles , Ohio
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therocks Offline
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Niles , Ohio
They had problems with the blower speed switch also.I replaced quite a few when I had my Rams.Rocky


Chrysler Firepower
Re: Blower fuse overheating [Re: therocks] #2588714
12/07/18 06:37 PM
12/07/18 06:37 PM
Joined: Jun 2003
Posts: 2,083
Haslet, Texas
RapidusMaximus Offline OP
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RapidusMaximus  Offline OP
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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

2016 Dodge Ram Hemi 1500
Re: Blower fuse overheating [Re: RapidusMaximus] #2588807
12/07/18 10:06 PM
12/07/18 10:06 PM
Joined: Jan 2003
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Omaha Ne
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TJP Offline
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TJP  Offline
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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

Re: Blower fuse overheating [Re: TJP] #2589508
12/09/18 06:53 PM
12/09/18 06:53 PM
Joined: Jun 2003
Posts: 2,083
Haslet, Texas
RapidusMaximus Offline OP
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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

2016 Dodge Ram Hemi 1500
Re: Blower fuse overheating [Re: RapidusMaximus] #2589527
12/09/18 07:39 PM
12/09/18 07:39 PM
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Lost and Spaced
bboogieart Offline
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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


I have mechanical Aptitude.
I can screw up anything.
Re: Blower fuse overheating [Re: bboogieart] #2589652
12/10/18 12:12 AM
12/10/18 12:12 AM
Joined: Jun 2003
Posts: 2,083
Haslet, Texas
RapidusMaximus Offline OP
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RapidusMaximus  Offline OP
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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

2016 Dodge Ram Hemi 1500
Re: Blower fuse overheating [Re: RapidusMaximus] #2589836
12/10/18 02:46 PM
12/10/18 02:46 PM
Joined: Sep 2003
Posts: 10,791
north of coder
moparx Online content
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north of coder
thanks for the update, and glad you got it sorted out !
beer


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