1st gen 3.5 LHS (1996) cooling

noticed Saturday its getting up to the half way point and not really cooling
down much from there. I changed the thermostat because i have been meaning
to do that anyway ( stuck with the stock temp) and the coolant temp sensor
wasn't reading the best when i tested it so i put another one for GPs. now
that i have changed those and gotten the air out of the system its better
but noticing that when it gets to the half way mark on the gauge like
always, it turns on the right fan, then its cools down but it takes it's
ever loving sweet time doing it. turning on the A/C at that point.turns off
the right fan and turns on the left fan. turn off the a/c and it goes back
to the right fan only. i was thinking they should both be running when its
hot, but maybe i am mistaken. my old FSM for my truck had full explanations
as to what happens at what point in the operation but my current manual
doesn't ( i know, i know ....shoulda invested in a REAL one )

when i had this issue with the 94 Concorde, the water pump was making noise
and you could tell. but I'm wondering at this point if i have a fan relay
or radiator issue. I'm going to go out in a few and wash out the radiator
fins to make sure I'm getting good air thru it. Any other factors i should
be looking for? this damn thing has 139,000 on it. i called the service
guy at the dealer i bought it from right after buying it 2 years ago(same
one the old lady that had it before had taken it to for all her work) and
they had service records of changing the water pump around 49,000 or so, but
it could need another one, especially after all the torture i put it through
in big city traffic day in and day out ( Florida weather is hell on it too).

 

Yes, you should -- and AFAIK you still can. Regardless, for the
SECOND generation (so YMMV), the FSM says:

OPERATION
The cooling system fans will operate at two speeds and are
simultaneously activated. The dual fan system improves engine
cooling and air conditioning performance in hot weather and
severe driving conditions, while reducing fan noise and power
consump ion.

The cooling fans will operate based on inputs to the
Powertrain Control Module (PCM). When fan operation is
determined necessary, the PCM provides a ground to the fan
relay control circuit.

So what you're seeing seems fishy.

 

The engine cooling fans for the 2nd gen do in fact act in tandem, i.e.,
they both are at the same speed (both off, both lo sped, both hi speed)
at any given moment. I'm not sure if the 1st gen does the same thing,
but I wondered about that too. You'd have to look at the schematics for
the first gen.

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

 

I have some manual information in '94 LH cars that says "On models with
dual electric fans, fans operate through a common relay and are
activated at same time." I don't know where I got this document that I
have - it does not appear to be direct from Chrysler, and I tend to
distrust aftermarket service information. But it sounds like it is a
safe bet that the fans should be working together like Joe said.

Could be a relay, fan motor, or wiring problem. It would be best if you
had the schematics.

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

 

"Could be a relay, fan motor, or wiring problem. It would be best if you
had the schematics."

yeah that was another reason i wanted to change the temp sensor aside from
the fact the resistance seemed off. i wanted to make sure i was getting a
good signal to everything. so i need to find what schematics i do have and
go from there.

 

You're not mistaken. You have a bad fan motor on the passenger's side.
Just finished fixing a similar problem on my wife's '93. The right-side
motor is a screwball thing with two sets of winding. On low speed, one
of its windings is powered from the car, the other acts as a generator
and drives the left-side fan. This causes both fans spin slowly on low
speed. On high speed, power is applied to the left fan directly and
also to the set of windings that was acting as a generator on the right
fan, so both fans get power directly from the car and spin fast. I think
that later in the first-generation LH car run, they changed it up so
that its one fan on low, BOTH fans on high. But either way, its never
"one fan on low, the other fan on high."

 

really. ok that might seem possible since we use AC so much in Florida, the
fan is running a lot. i didn't notice the passenger side fan seems to have a
large motor housing. noticed the right one comes on even when its not hot,
as long as the A/C is on.


when i hadn't quite gotten all the air out the first time Saturday, the
gauge went to the half waypoint, right side fan came on, gauge moved a
little bit more towards hot, then both came on at once and sped up some. so
the extreme high seems to work, but i'll look into the right side fan
anyway. Also wondering if A/C pressures are effecting it.

fan relays seem to work, but all the info i have is a diagram showing the
color of one wire sending power to it and the pin number on the power
connector that sends power to it. no info on which blade does what and what
you should measure etc. anyway with low side relay out of the car the left
fan kicks in and takes over. otherwise right side seems to do the work. so
the 2 sets of wiring info you gave seems about right.



i thought the left one was the one running for A/C though,

 

Wow. That is screwball. You sure about that? I'd love to see the
schematics for that. Anyway you could email that to me?

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

 

ditto

 

found this today....

DESCRIPTION
All models use electric motor driven fans. The fan modules include a motor
support and shroud. The module is fastened to the radiator by screws with
U-nuts and retaining clips.

OPERATION
The dual fan module is a combination of 2 fans mounted in a one piece shroud
which operate at two speeds and are simultaneously activated. The dual fan
system improves engine cooling and air conditioning performance in hot
weather and severe driving conditions, while reducing fan noise and power
consumption.

CAUTION: Attempts to reduce high temperature gauge reading by increasing
engine speed, at the same vehicle speed, can increase high temperature.

CIRCUIT OPERATION
The radiator fan system uses two relays located in the Power Distribution
Center (PDC) . One relay is used for LOW speed fan operation and the other
is for HIGH speed operation. The Powertrain Control Module (PCM) controls
the operation of the relays depending on engine coolant temperature and/or
A/C operation.

Power for the coil side of both relays is provided on circuit F18. This
circuit is protected by a 10 amp fuse located in cavity 20 of the junction
block. Power for the contact side of the relays is provided on circuit A16.
This circuit is protected by a 40 amp fuse located in cavity D of the PDC.

When LOW speed fan operation is required, the PCM grounds circuit C24. This
causes the contacts in the relay to CLOSE connecting circuits A16 and C23.
Circuit C23 connects from the relay, and is spliced to the low speed fan
motor and the Radio Frequency Interference (RFI) suppression module. Ground
for the motor is provided on circuit Z1, which terminates at the left front
frame rail.

When HIGH speed fan operation is required the PCM grounds circuit C27. This
causes the contacts in the relay to CLOSE connecting circuits A16 and C25.
Circuit C25 connects from the relay, and is spliced to the high speed fan
motor and the RFI suppression module. Ground for the motor is provided on
circuit Z1, which terminates at the left front frame rail.

Copyright © 2008 ALLDATA LLC

 

Did that come from an Alldata account? If so, it should also give you
access to the schematic right out of the FSM.

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

 

update. new fans working much better. new ones from local dealer were
700.00 bucks! i went parts jobber and got them for 254. now the only issue
is a short in the high side. jumping it only turns on the low side fan so
i'll need to do some wire searching tomorrow night.

 

yeah there's an updated TSB on the wiring diagram
NUMBER: 26-10-95A



i can email it to you if you want.....



also found Cooling Fan - Noise/Poor Idle Quality
NO: 18-20-96

 

I don't think its actually detailed in the FSM (Rob posted a very good
verbal description from alldata in a subsequent post). I figured out
what was going on with a DVM and some experimentation when my wife's car
suffered its first fan motor casualty a few years back.

 

Well, now I don't feel so bad about paying $280 (tax and shipping
included) for my new module. It does still cheese me off that I can't
still get a replacement passenger-side motor like I did the first time I
had problems years ago. Everywhere I went they had plenty of DRIVER side
motors- but in my experience they never fail. The original one on wife's
93 was still working fine.

 

254.00 for mine at CARQUEST. everyone else i called could get them in 3
days, but that does help me get back and forth to work.

WARNING! they and a lot of other parts dealers carry DORMAN? fans now and i
was told this is a new product for them. i got my new one and it worked for
about a day and half. the connections to the high side fan (drivers side)
was loose all the time and the passenger side fan was doing all the work,
but then it got to the point it got hot and stopped working. the parts guy
that originally sold it to me said they have an issue with their quality
from time to time (duhhhh) but its lifetime warranted. so out it came and
back for another. works fine now.

also the parts guy at my local Chrysler told me he could maybe get me a
right side motor if i needed one but there was only 7 or 8 left, and they
would be about a week or 2 coming, and no guarantees on that. also he said
they superseded it with the full unit (both fans and shroud) since they were
only selling about 5 right side motors a year and that was nationwide!