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98 Chevy Blazer window, wiper, blower broken. What is an MFS?
Sent to Car Experts September 02 02:53 AM

HELP!...I have a 1998 Chevy Blazer that has some electrical problems. Aparently this in a common problem with this year and model as I was able to find on this website: www.suvoption.com/1998ChevyBlazerProblem.html

It say that installing an MFS may fix the problems, but I cannot find any other source to explain what an MFS is or where it would be installed. Some of the problems are wipers that sometimes stop working and driver's side electric window that wont work. I have both of these problems. Additionally other common problems also sometimes fixed by the MFS are: the trip odometer may stop working and the blinker may make the blinking noise when the blinker isn't on.

My blower motor also works sometimes but hasn't worked for a couple weeks now. This means my A/C wont blow cold air and my defroster wont unfog my windshield.

The driver window is irritating, but the other two problems are life-threatening because my windshield can suddenly become impossible to see through due to heavy rain or sudden fogging.

As I said before, the motors on all 3 of these components work fine sometimes, but then suddenly wont work at all, so I believe it is an electrical control component or loose wire rather than a defective motor.

Aparently installing the MFS may fix the problem, but I haven't been able to figure out what it is and where it goes.

Please, if anybody has any suggestions...please respond.

 

Optional Information:
1998 Chevrolet BLAZER V6 vortec

Customer (name blocked for privacy)
Answer
September 2 10:44 AM (7 hours and 51 minutes and 22 seconds later)
         
REPLIEDCheck Mark
Those kinds of web sites scare me.I'll tell you why,MFS stands for multifunction switch and is located in your steering column below the steering wheel.It has nothing to do with your power window problem or your blower motor problem.That site infers that it can.To fix your wipers you most likely need a wiper motor cover/pulse board.To check your blower motor you need to unplug it and place a test light across the two wires.Operate the switch in different positions and see if the test light comes on.If it does the blower motor is bad if it doesn't the blower motor fuse may be blown.We can get into more detail as needed if that's not the case.the drivers side window motor may be bad that is fairly common but we would need to remove the door panel to check for power at the motor connector in the same manner that the blower was checked exept by operating the switch for the window to see if the test light comes on in both directions.You can change the wiper motor cover in ten minutes yourself.It's mounted on the wiper motor and held on with three small torx screws.


Master ASE Certified.L1 Advanced Engine Performance Certified.Pa Emission Repair Technician.Just Answer Car Category Mentor.
Reply
September 2 1:49 PM (3 hours and 4 minutes and 47 seconds later)
         
Reply to Davo's Post: Yeah, I spent about 6 hours online last night and after about 50 sites, I was able to figure out everything that you told me. I was thinking it was one problem causing all of these items, but I think after reading - none of these items are related at all.

The confusing part is that ALL of these items are intermittent. They work perfect sometimes and later not at all...making me think it was some kind of control problem. After researching, I believe it is more likely a manufacturing problem like with the soldering inside the wiper motor. Several years of these wiper motors have been recalled for that circuit board up to the 1997 Blazer...but the 1998 isn't included in the recall, but for some reason the 98 hasn't been added yet even though I found well over a 100 postings for this problem on the 1998. I have a phone # for Chevy to get this fixed, so I'll probably get them to do that for free since the 98 should be added soon.

My main problem is the fan motor. It stopped working for a couple days and then it worked for a couple days and now it hasn't worked for a week or two. I was able to determine that there is a Blower Motor Resistor and a Blower Motor Relay. I found where the Resistor is located and it looks easy to replace. I don't know where the Relay is, but I was told that it was near the Resistor. The Blower Motor never made any kind of noise like it was beginning to fail, it just stopped working. In your experience, which of the 3 components is most likely the culprit? Do you know where it is and cannot it be easily tested or troubleshooted?

On the driver's window motor. It has worked on and off for 3 years now...sometimes for months at a time either on or off. It's off now. I found a website that shows step-by-step how to replace the motor and regulator but I'm not sure this applies to the 1998 model: http://www.usedpartscentral.com/tech/page1.htm

Does this look about right to you? Is it a lot easier to replace the motor and regulator together? If I pay someone to do it - what should it cost approximately? Parts/Labor best guess or estimate? Is it common for the motor to stop and start working for months or does it sound more like a loose wire? When the switch is activated - it does cause the dash lights to dim, so power is going somewhere and I've already troubleshot the switch with a junkyard one without results.

I was able to find all of the same answers that you provided (although it took 6 hours), but I appreciate the quick response and confirmation that my research came to the same conclusions as you suggested. Replacing the Multi-Function Switch is definitely not the solution as the one website suggested.

I believe I have researched my problems as far as possible and would appreciate any answers to my NEW questions (Blower Resistor and Relay, Window Motor replacement) because I am done with my internet marathon.

Thanx,

Todd
Answer
September 2 2:04 PM (14 minutes and 43 seconds later)
         
REPLIEDCheck Mark
The first thing to do is test for power at the blower mtor with the key on.Then if you don't have it check the fuse for it.For the blower to not work any other way the resistor and the relay would both have to be bad.The blower mtor runs on high through the relay and on lower speeds it goes through the resistor.The switch could be bad that's why we need to start at the motor and work our way back.If the switch is good you will have power on different resistor terminals in different fan settings.You follow me so far?It may be easier to diagnose the blower if we go one step at a time though.You will need a test light and you can get them under ten bucks.The site with the window instructions is good with one exception.You need to check the power and ground with a test light not a voltmeter.The instructions on doing the regulator are accurate.I can't even guess on the part price for the regulator but I would just change the motor if it were me.Should be 1 and 1/2 to 2 hours labor at your local labor rates.


Master ASE Certified.L1 Advanced Engine Performance Certified.Pa Emission Repair Technician.Just Answer Car Category Mentor.
Reply
September 2 7:57 PM (5 hours and 52 minutes and 52 seconds later)
         
Reply to Davo's Post: If you don't mind, I'd like to a little more specifics on testing the motor/resistor/relay. I'm heading out of town for a couple days in a few minutes, but when I get a chance I'll take a look under the hood so I can see what I'm looking at. If you can respond with your e-mail address, I'll respond with "accept", because you answered my questions--Thanx,

Todd
toddebarton@msn.com
Answer
September 3 7:06 AM (11 hours and 9 minutes and 47 seconds later)
         
ACCEPTEDCheck Mark
When you get back just relist this question.I would be in violation of the site rules to communicate with you by email.I hope you understand my position.We will discuss whatever you need to know in this question.


Master ASE Certified.L1 Advanced Engine Performance Certified.Pa Emission Repair Technician.Just Answer Car Category Mentor.
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