Blower Resistor 1998 Intrepid 2.7

For the third time this year the Blower Resistor has failed, leaving me with
Off and Full.
The dealer replaces them as they have a 1 year warranty. The problem seems
to be the location, the coils corrode.
Has anyone any suggestions how to prevent this corrosion occurring. Its not
the price its the contortions one has to assume tochange it!
Keith

 

Corrosion?? Where do you live? The blower resistor is concealed in the
firewall. It's not exposed to the elements. I sense it's possibly
receiving too much voltage. Very Interesting, indeed.

 

When the resistor pack blows repeatedly, the problem is almost always
the blower motor needing to be replaced. Replace the blower motor, and
the resistor pack will quit failing.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

hi keith your problem is not corrosion but the quality of the previous
resistors installed.mopar has released a revised part number blower
resistor . i suggest you get that one installed.

 

actually it's exposed to moisture from the a/c system and is clearly visible

 

the new style reistor is a sealed unit. and the evaporator coil sits in
front of the resisitor so you may be getting moisture from other source

 

Blower Motor bad

 

Please explain: The Blower motor is either off or full on. How can a bad
blower motor affect the resistor that sets the different speeds.
I can pick up a motor for $30 from a wreckers if it will rectify the problem
(blown resistors etc)

Keith

 

When the motor is full on, the resistors are completely bypassed (+12V
applied directly to motor, no current thru the resistors) - so motor
will still run on hi speed even with burned up resistors. When
everything was good, the slower motor speeds were controlled by running
the power to the motor thru the resistors (resistors and motor in series
- resistors drop voltage, motor sees less voltage, runs slower). When
the motors age, for some reason, they start pulling more current (could
be due to partially shorted windings *or* bearings/bushings starting to
bind up *or* brush dust building up on commutator and partially shorting
between the commutation bars). Whatever the cause (of lower effective
resistance => higher current) in the motor, the resistors are not
designed for the higher current/lower resistance load, and they burn up
(it's called cheap design with no safety factor).

Clear as mud?

Motor from a junk yard may or may not develop the same problem (as could
a new motor, but likely not for a long while). Used motor => risk. New
motor => no problem at least for a while (how long before the original
motor started blowing the resistors?).

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Thanks Bill, quite clear in fact.
It took about 3 years before4 the first resistor went another 3 years before
the next one then 5 months.
I have bought the one from the wreckers and will put it in tomorrow. If it
works all well and good , if not at least I get practice in swopping it
over.
Incidentally I have the 2.7 Engine with 255000 on the clock, no sludge, no
oil problems so a defective blower is no big deal.
Keith

 

That's a good record on tne 2.7L. Are you still on the original timing
chain and water pump? I'm over 150k miles on mine and contemplating
ordering the parts with the idea of putting them in when the mood
strikes (Spring?).

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Yes, still on original timing chain and water pump.
A chrysler dealer told me that I should replace the timing 'belt' at 100,000
km. They did not seem to realise it was a chain!

 

sorry to inform you bill but those credit card type resistors for blowers are
made so any moisture can get to the circutboard and cause issues
there was a redesign after 3 years and it does work a whole lot better

 

it still runs thru resistor but as a default mode so it has a working blower in
case of failure as designed
a blower that is using to many amps in it's duty cycle can burn out a resistor
prematurely

 

LOL! Not surprised. I had to show a dealer in the FSM that the tranny
and diff on the LH cars have separate sumps.

Wow - you're at 255k on original chain and pump! I have considered just
letting 'er ride and see what happens - I'm tempted again with your
experience. Some claim that the water pump coming apart is more of a
risk than the chain, but of course if you do one, you might as well do both.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Am I naive? I assume a chain just wears gradually as opposed to a belt that
'snaps'. This gives you time to schedule replacement and, of course, do the
water pump at the same time.
Keith

 

The chain *will* gradually wear, and eventually will develop slack that
the tensioner cannot compensate for. Based on my reading, there is also
a real-world risk that the water pump will lock up or come apart and
wreak havoc - ripping the timing chain out and causing other damage -
supposedly there are several real-world examples of this with the 2.7L.
The third risk with the 2.7, due to it's being prone to fatal
sludging, is that the oil pressure-driven chain tensioner can loose oil
pressure and relax the chain, with disasterous results.

Be aware that the 2.7L is an interference engine (i.e., if the cams and
crankshaft become unsynchronized due to slipped or broken chain, the
valves and pistons can collide - potentially very expensive).

The good news for you is that your engine is apparently not falling
victim to sludge - either due to very good maintenance (oil changes,
etc.) and/or mostly hiway driving (vs. short trip, and/or stop and go).

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

I'm not sure exactly what you're saying there, but no current goes thru
any resistors when the motor is on hi speed. It may flow thru a solid
metal path inside the resistor pak for hi speed, but not thru any
resistors per se - maybe that's what you're saying in the first part of
your post.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')