I've heard Bill and Mike both talk about a separate diode that's been
replaced at times....what is this diode for?
Again, I can find the replacement instructions for it in my service manual,
but haven't been able to find a description of what it's for!


"Jo Bo" <jromas@columbus.rr.com> wrote in message
news:6_9Cd.3818$iu5.37@fe2.columbus.rr.com...
> It's a thermal fuse. You can get a replacement at Radio shack or just
> solder a wire around it. Mine blew because the motor needed lubed. Yes,
> it's just like the one used on VW's.
>
> JoBo
>
> "Pat Moore" <pmoore@gatecliff.com> wrote in message
> news:10tg90dga95ta10@corp.supernews.com...
>> We're working on a friend's "new" 94 Cherokee and have replaced the
>> busted
>> heater fan motor. We then tracked why the fan only worked on "High" to
>> an
>> open
>> component in the heater resistor. It's shown as a switch in the wiring
>> diagram, and physically resembles a silicon diode. Shorting across it
>> restored all four fan speeds. Does anyone know what that diode-looking
>> thing
>> is? And why it's there? I hate to buy a new resistor pack just to replace
>> the diode (?).
>>
>>
>
>

 

I've heard Bill and Mike both talk about a separate diode that's been
replaced at times....what is this diode for?
Again, I can find the replacement instructions for it in my service manual,
but haven't been able to find a description of what it's for!


"Jo Bo" <jromas@columbus.rr.com> wrote in message
news:6_9Cd.3818$iu5.37@fe2.columbus.rr.com...
> It's a thermal fuse. You can get a replacement at Radio shack or just
> solder a wire around it. Mine blew because the motor needed lubed. Yes,
> it's just like the one used on VW's.
>
> JoBo
>
> "Pat Moore" <pmoore@gatecliff.com> wrote in message
> news:10tg90dga95ta10@corp.supernews.com...
>> We're working on a friend's "new" 94 Cherokee and have replaced the
>> busted
>> heater fan motor. We then tracked why the fan only worked on "High" to
>> an
>> open
>> component in the heater resistor. It's shown as a switch in the wiring
>> diagram, and physically resembles a silicon diode. Shorting across it
>> restored all four fan speeds. Does anyone know what that diode-looking
>> thing
>> is? And why it's there? I hate to buy a new resistor pack just to replace
>> the diode (?).
>>
>>
>
>

 

Hi Steve,
Not I. I wouldn't even replace a diode in an alternator, it's
cheaper to buy the rebuild. And we haven't figured out what caused the
Original Poster's to pop, like an internal short in his resistor pack?
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

SteveBrady wrote:
>
> I've heard Bill and Mike both talk about a separate diode that's been
> replaced at times....what is this diode for?
> Again, I can find the replacement instructions for it in my service manual,
> but haven't been able to find a description of what it's for!

 

Hi Steve,
Not I. I wouldn't even replace a diode in an alternator, it's
cheaper to buy the rebuild. And we haven't figured out what caused the
Original Poster's to pop, like an internal short in his resistor pack?
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

SteveBrady wrote:
>
> I've heard Bill and Mike both talk about a separate diode that's been
> replaced at times....what is this diode for?
> Again, I can find the replacement instructions for it in my service manual,
> but haven't been able to find a description of what it's for!

 

Hi Steve,
Not I. I wouldn't even replace a diode in an alternator, it's
cheaper to buy the rebuild. And we haven't figured out what caused the
Original Poster's to pop, like an internal short in his resistor pack?
God Bless America, ßill O|||||||O
mailto:-------------------- http://www.----------.com/

SteveBrady wrote:
>
> I've heard Bill and Mike both talk about a separate diode that's been
> replaced at times....what is this diode for?
> Again, I can find the replacement instructions for it in my service manual,
> but haven't been able to find a description of what it's for!

 

Sorry Bill....I know I had heard it on here a couple of times and assumed it
was one of the more knowledgables (Mike, you, etc..).

Bill is right....if the diode blew...it did for a reason.
Check the heater fan rotor....it should be easily turnable with your hand.
Give it a hard tug and see if it spins (have to take belt off of course--or
gear...); it should turn a couple of times.
If the bearings go, then the motor might be drawing more current than
normal, which would kill your diode.

You might check the diodes ratings (look up it's part number) and also hook
up an Ammeter in series (in place of the diode) and check for the current
draw and compare this to the diodes rating.
Be aware that the diode will not be in place at this point so be sure to
disconnect your probes before turning off the switch as the collapsing
magnetic field will have a free path back up the line and thru the meter and
on....(disconnecting the probes break the circuit before the field can
collapse back in to the line.)

Be sure you use the proper scale on your meter too....most regular meters
are only rated for 10A, which may not be all that much....so definately
check the diode part rating first!



"L.W. ("ßill") ------ III" <----------@***.net> wrote in message
news:41D9B2BB.A3F503CA@***.net...
> Hi Steve,
> Not I. I wouldn't even replace a diode in an alternator, it's
> cheaper to buy the rebuild. And we haven't figured out what caused the
> Original Poster's to pop, like an internal short in his resistor pack?
> God Bless America, ßill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> SteveBrady wrote:
>>
>> I've heard Bill and Mike both talk about a separate diode that's been
>> replaced at times....what is this diode for?
>> Again, I can find the replacement instructions for it in my service
>> manual,
>> but haven't been able to find a description of what it's for!

 

Sorry Bill....I know I had heard it on here a couple of times and assumed it
was one of the more knowledgables (Mike, you, etc..).

Bill is right....if the diode blew...it did for a reason.
Check the heater fan rotor....it should be easily turnable with your hand.
Give it a hard tug and see if it spins (have to take belt off of course--or
gear...); it should turn a couple of times.
If the bearings go, then the motor might be drawing more current than
normal, which would kill your diode.

You might check the diodes ratings (look up it's part number) and also hook
up an Ammeter in series (in place of the diode) and check for the current
draw and compare this to the diodes rating.
Be aware that the diode will not be in place at this point so be sure to
disconnect your probes before turning off the switch as the collapsing
magnetic field will have a free path back up the line and thru the meter and
on....(disconnecting the probes break the circuit before the field can
collapse back in to the line.)

Be sure you use the proper scale on your meter too....most regular meters
are only rated for 10A, which may not be all that much....so definately
check the diode part rating first!



"L.W. ("ßill") ------ III" <----------@***.net> wrote in message
news:41D9B2BB.A3F503CA@***.net...
> Hi Steve,
> Not I. I wouldn't even replace a diode in an alternator, it's
> cheaper to buy the rebuild. And we haven't figured out what caused the
> Original Poster's to pop, like an internal short in his resistor pack?
> God Bless America, ßill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> SteveBrady wrote:
>>
>> I've heard Bill and Mike both talk about a separate diode that's been
>> replaced at times....what is this diode for?
>> Again, I can find the replacement instructions for it in my service
>> manual,
>> but haven't been able to find a description of what it's for!

 

Sorry Bill....I know I had heard it on here a couple of times and assumed it
was one of the more knowledgables (Mike, you, etc..).

Bill is right....if the diode blew...it did for a reason.
Check the heater fan rotor....it should be easily turnable with your hand.
Give it a hard tug and see if it spins (have to take belt off of course--or
gear...); it should turn a couple of times.
If the bearings go, then the motor might be drawing more current than
normal, which would kill your diode.

You might check the diodes ratings (look up it's part number) and also hook
up an Ammeter in series (in place of the diode) and check for the current
draw and compare this to the diodes rating.
Be aware that the diode will not be in place at this point so be sure to
disconnect your probes before turning off the switch as the collapsing
magnetic field will have a free path back up the line and thru the meter and
on....(disconnecting the probes break the circuit before the field can
collapse back in to the line.)

Be sure you use the proper scale on your meter too....most regular meters
are only rated for 10A, which may not be all that much....so definately
check the diode part rating first!



"L.W. ("ßill") ------ III" <----------@***.net> wrote in message
news:41D9B2BB.A3F503CA@***.net...
> Hi Steve,
> Not I. I wouldn't even replace a diode in an alternator, it's
> cheaper to buy the rebuild. And we haven't figured out what caused the
> Original Poster's to pop, like an internal short in his resistor pack?
> God Bless America, ßill O|||||||O
> mailto:-------------------- http://www.----------.com/
>
> SteveBrady wrote:
>>
>> I've heard Bill and Mike both talk about a separate diode that's been
>> replaced at times....what is this diode for?
>> Again, I can find the replacement instructions for it in my service
>> manual,
>> but haven't been able to find a description of what it's for!

 

That is what VW dealer personnel tell me. If the heater blower pack thermo
fuse blows = replace blower AND resistor pack.

You take a chance if you remove the fuse and jump the wires to get the other
blower speeds. ;-)


"SteveBrady" <steve.brady@(remove this)rogers.com> wrote in message
news:hZSdnbAG4ejKVETcRVn-sg@rogers.com...
> Sorry Bill....I know I had heard it on here a couple of times and assumed
> it was one of the more knowledgables (Mike, you, etc..).
>
> Bill is right....if the diode blew...it did for a reason.

 

That is what VW dealer personnel tell me. If the heater blower pack thermo
fuse blows = replace blower AND resistor pack.

You take a chance if you remove the fuse and jump the wires to get the other
blower speeds. ;-)


"SteveBrady" <steve.brady@(remove this)rogers.com> wrote in message
news:hZSdnbAG4ejKVETcRVn-sg@rogers.com...
> Sorry Bill....I know I had heard it on here a couple of times and assumed
> it was one of the more knowledgables (Mike, you, etc..).
>
> Bill is right....if the diode blew...it did for a reason.