I have a 98 Jimmy 120000kms on it and the blower motor rattles and squeaks
when heater control selector switch is on position 1, especially on 2 and
slightly gets quieter on position 3 and 4(blower motor full speed). This
rattling is driving me crazy because wife drives it and I get all the
complaints. I've looked under the hood to see how to change blower motor but
the unit is sealed into a plastic factory housing . With previous GM
vehicles I've owned changing blower motor was never a problem and with the
last GM vehicle I had the same squeak and rattling and it turned out to be a
bad ground on blower.
Can anyone offer any help on how to change blower unit or maybe I have to
grease a bearing or something?
If memory serves, the blower motor is located on the far passenger side of
the engine bay, just behind the shock tower. It is external to the HVAC
system, i.e.) loosen the bolts and it pulls right out of it's mount.
According to GM-SI (service information) You are supposed to cut thru
the blower motor access cover. Then reseal it in place with Weather
It also states that the VCM must be removed first, as well as the
coolant tank. Removing the VCM requires reprograming it. So unless you
have a Tech 2 or equil aftermarket equipiment, this is not a service you
There maybe a better methiod of removial then the GM-SI way.
This is not right. You aren't reading the service manual correctly.
It's giving you the procedure for removal "or" replacement. You
can remove the VCM without having to reprogram it. I've removed
them a number of times to gain access to stuff.
Yanking the battery cable is the same as "removing" the VCM right? And the
VCM doesn't need to be reprogrammed when your battery craps out and needs
replaced every 5-6 years right?
So why would the service manual state that removal necessitates
reprogramming? Is this GM's way of making sure any newer ROM flashes are
applied when the VCM has to be mucked with anyways?
I don't know why GM-SI says on W-cars like my Century to remove the
negitive battery cable when changing the blower motor. It is a Key on
only powered circuit. I just turned the key off, losened the moter,
removed the clip for the resistor, droped the moter and reversed for the
install. Only problem with the job was I knew the resistor was bad,
and the salvage yard didn't send a one with the motor. Yet what can you
expect on new years eve?
I bought GM-SI 1998 up so I could do three things:
Save on space, not have to worry about books getting greasy prints,
and be able to have a copy in hand to explaine to customers exactly
the repair done, and how it's perfromed.
I am using GM-Sevice Information Softwear. Document ID# 422237
1998 GMC Truck Jimmy - 4WD.
I have yet to service one of these where I have had to do anything
where VCM remoial or disconnecting was required.
Step#2 in removial according to GM-SI:
Remove the PCM/VCM. Refer to PCM Replacement/Programming or VCM
Replacement/Programming in Engine Controls.
Step#11 in installation according to GM-SI:
Install the PCM/VCM. Refer to PCM Replacement/Programming or VCM
Replacement/Programming in Engine Controls.
I looked for a asnwer to the blower motor cover, and saw the bit about
PCM/VCM removial & reprograming. This is a area where your dealer
experiance prevails. You proabably have worked on a lot of these trucks.
Where they are just now getting old enough for people not to take them
to dealer service departments.
I guess my post might have sounded like I'm giving you sh*t for
the info. Not my intent, just mentioning that "that" section of the
service manual is not saying that anytime you "disconnect" the
VCM you have to reprogram. I use SI every day, and it's very
obscure and useless in many instances. Since they have moved
away from the paper manuals, the quality of the service manuals
has gone way downhill. A lot of it is just plain wrong, especially
removal and installation procedures on new models. I had to
do an oil pan gasket on a Malibu Maxx the other day, it has
a different subframe, exhaust setup, motor mount set, but uses
the same basic old 3.1/3.4/3.5 engine in it. SI says to remove
this/that and the other, I look....doesn't make any sense...so I
just figured out the procedure on my own. Worked out much
better "my way". Hopefully, the vast majority of techs will
attempt to follow SI, spend a whole lot more time on the job
then is necessary, and push up the average time spent on the
job. This in turn leads to higher labour estimates for GM warranty
time when they put actual times in place (GM now pays straight
time for many operations on new models, takes the average time
from across all the different dealers nationwide that perform "that"
job, and then determines their warranty times from there) Which
will benefit me.
I know you were not giving me any guff. Just your perspective.
Beleave it or not, when someone knows what they are talking about I listen.
You may or may not remember me from alt.autos.gm. Yet I remember you.
Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here.
All logos and trade names are the property of their respective owners.