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.

 

I am not sure what diode you are thinking of, there are a few I have
mentioned.

The resistor pack either has a thermal fuse like most are saying or a
diode. They serve different purposes. I haven't taken one apart to see
it or I would know.

If it is a thermal fuse, it is there to blow before heat can damage the
wiring, something like a fuse link wire. If it is a diode, it is there
to direct the flow of power in one direction only. Without it something
else can be affected when the heater turns on and something will likely
let the smoke out and quit.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

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!
>
> "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 am not sure what diode you are thinking of, there are a few I have
mentioned.

The resistor pack either has a thermal fuse like most are saying or a
diode. They serve different purposes. I haven't taken one apart to see
it or I would know.

If it is a thermal fuse, it is there to blow before heat can damage the
wiring, something like a fuse link wire. If it is a diode, it is there
to direct the flow of power in one direction only. Without it something
else can be affected when the heater turns on and something will likely
let the smoke out and quit.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

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!
>
> "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 am not sure what diode you are thinking of, there are a few I have
mentioned.

The resistor pack either has a thermal fuse like most are saying or a
diode. They serve different purposes. I haven't taken one apart to see
it or I would know.

If it is a thermal fuse, it is there to blow before heat can damage the
wiring, something like a fuse link wire. If it is a diode, it is there
to direct the flow of power in one direction only. Without it something
else can be affected when the heater turns on and something will likely
let the smoke out and quit.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

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!
>
> "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 (?).
> >>
> >>
> >
> >

 

Mike Romain did pass the time by typing:
> I am not sure what diode you are thinking of, there are a few I have
> mentioned.
>
> The resistor pack either has a thermal fuse like most are saying or a
> diode. They serve different purposes. I haven't taken one apart to see
> it or I would know.
>
> If it is a thermal fuse, it is there to blow before heat can damage the
> wiring, something like a fuse link wire. If it is a diode, it is there
> to direct the flow of power in one direction only. Without it something
> else can be affected when the heater turns on and something will likely
> let the smoke out and quit.

It's also that a thermal fuse will often look like a switch in a schematic.
i.e. _____/ _____

where a diode will look like this ---|>|----

--
DougW

 

Mike Romain did pass the time by typing:
> I am not sure what diode you are thinking of, there are a few I have
> mentioned.
>
> The resistor pack either has a thermal fuse like most are saying or a
> diode. They serve different purposes. I haven't taken one apart to see
> it or I would know.
>
> If it is a thermal fuse, it is there to blow before heat can damage the
> wiring, something like a fuse link wire. If it is a diode, it is there
> to direct the flow of power in one direction only. Without it something
> else can be affected when the heater turns on and something will likely
> let the smoke out and quit.

It's also that a thermal fuse will often look like a switch in a schematic.
i.e. _____/ _____

where a diode will look like this ---|>|----

--
DougW

 

Mike Romain did pass the time by typing:
> I am not sure what diode you are thinking of, there are a few I have
> mentioned.
>
> The resistor pack either has a thermal fuse like most are saying or a
> diode. They serve different purposes. I haven't taken one apart to see
> it or I would know.
>
> If it is a thermal fuse, it is there to blow before heat can damage the
> wiring, something like a fuse link wire. If it is a diode, it is there
> to direct the flow of power in one direction only. Without it something
> else can be affected when the heater turns on and something will likely
> let the smoke out and quit.

It's also that a thermal fuse will often look like a switch in a schematic.
i.e. _____/ _____

where a diode will look like this ---|>|----

--
DougW