How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask Pete Your Own Question

Pete
Pete, Auto Mechanic
Category: Chevy
Satisfied Customers: 14193
Experience:  14 years GM dealer Technician.
Type Your Chevy Question Here...
Pete is online now
A new question is answered every 9 seconds

Chevrolet Silverado 1500: Is there a way to test your 4x4 actuator

Resolved Question:

Is there a way to test your 4x4 actuator in a 2002 silverado to see if it is actually working? I have replaced with new actuator and new tranfer case control switch and still cannot get my truck to go into 4x4. Switch just blinks and blinks 4hi or auto. I also have chased wires to make sure of bad wires. No idiot lights on either. I am wondering if my new actuator is not working properly. A while back when the old actuator was in, i pulled the skid plate and tapped on the actuator and it started going into 4x4 like a new one. So i thought for sure the actuator was my culprit.
Submitted: 2 years ago.
Category: Chevy
Expert:  Pete replied 2 years ago.
Hello,I will be glad to try and assist you with this,Welcome to Just Answer.

Hi.

I have supplied power and ground to this actuator before just briefly to make sure it works properly.You don't want to hold power and ground there to long as it can turn the motor/actuator to far and then it would have to be replaced.

To do this I located the fatter black and fatter red wire and provided a ground to the black wire and touched power to the red wire and it should move if it is working.

If it is working then the fault may be with the transfer case control computer itself as I have seen old actuators short out internally and then feed back this short to the transfer case computer and short it out as well.

The fault codes should be checked as well in the transfer case computer with a scan tool that can communicate with this computer to see what codes have set as this will aid in the diagnosis.A local parts store might check the fault codes free of charge as I have heard of before.


Let me know if you need anything else,click accept if you feel satisfied with your answer as this is how I get credited for my time,Thanks Pete!
Happy Holidays!
Customer: replied 2 years ago.
i dont understand where these wire are that you are talking about. There are no red wires on my actuator plug. Cant i just turn the actuator out, plug it in, start the truck and hit the button and it should turn?
Expert:  Pete replied 2 years ago.
Is this the transfer case actuator you are speaking of or the front differential actuator?
Customer: replied 2 years ago.
front differential, the one that engages the 4x4
Expert:  Pete replied 2 years ago.
O.k.

You can check this by removing it from the front differential,then start the vehicle and try and engage the 4wd it should move out when engaged and move back in when disengaged.

There isn't a way to really jump power and ground to this actuator as it can damage this unit causing it to be replaced.

The most common component to fail on this vehicle that I have seen several times before is the transfer case electric shift actuator as it can fail internally electronically.When this actuator doesn't engage properly the front differential actuator wont engage properly as well.

From what you have described here the transfer case actuator sounds like what you may have at fault as it is very common to cause this issue here.

I would still have the fault codes checked in the transfer case computer by a scan tool or code reader that can communicate with this computer to see what codes have set.Then from there it can be diagnosed as to what component is at fault and needs replaced.

Let me know if you need anything else,click accept if you feel satisfied with your answer as this is how I get credited for my time,Thanks Pete!
Happy Holidays!
Customer: replied 2 years ago.

Testing the actuator the way you described, if i hit the 4hi button inside the truck, would the 4hi button actually quit blinking and say it is locked into 4hi (if the acutator is functioning properly)? I have tested both the old and new actuator and neither of them seem to be working. Is it going to be very obivous when they are moving in and out?

Expert:  Pete replied 2 years ago.
Yes once the cycle is complete meaning once first the transfer case actuator cycles to 4 high (which you should be able to hear coming from under the center of the vehicle as it is very noticeable) and then the front differential actuator engages the light quits blinking and stays lit in 4wd hi.Same as when you switch back to 2wd you can hear the motor on the transfer case and then the front actuator will move as well and the light will quit blinking and stay lit in 2wd.

If you do not hear the noise from the transfer case which should be heard with your drivers door open when pressing 4high then this can indicate the actuator on the transfer case is faulty and needs replaced.

But the fault codes should be checked first to verify this is at fault as well as some testing from the fault code that is set.

Let me know if you need anything else,click accept if you feel satisfied with your answer as this is how I get credited for my time,Thanks Pete!
Happy Holidays!
Customer: replied 2 years ago.

There are no check engine or service 4wd lights present on my truck. i can hear the noice you described coming from the center of the vehicle but the front differential does nothing. I also want to add that this truck has only 50k miles.

Expert:  Pete replied 2 years ago.
It would be obvious when the actuator moves in and out for the front differential.

If you hear the transfer case motor engaging and disengaging then the front actuator should move as well unless there is a fault with the new actuator or a fault with the transfer case computer which is possible since the vehicle does have a 4wd fault but isn't giving you any messages on the dash as there should be a 4wd message letting you know there is a fault detected and a faulty computer wouldn't see the fault to turn on this message.

Even at low miles I have seen the 4wd computer fail internally and need replaced as well as other components for the 4wd system fail like the actuator on the front diff. and on the transfer case.

The best thing to do is to have the fault codes checked just to make sure the 4wd computer hasn't set any codes and to make sure communication can be established with the 4wd computer with a scan tool that has this capability to see if it is the computer at fault here.

Let me know if you need anything else,click accept if you feel satisfied with your answer as this is how I get credited for my time,Thanks Pete!
Happy Holidays!
Customer: replied 2 years ago.
i am going to go pick up another new front differential actuator and just plug it in and see if it will engage. I hate to keep throwing money at the problem. My local napa is good about returning parts for troubleshoot as long as they are not special order. If this doesnt work then i will have to see about getting scanned.
Expert:  Pete replied 2 years ago.
Throwing parts at a vehicle is never a good option to try and resolve it this is why it is best to have the fault codes checked and to have it tested to see if there is another component at fault like the 4wd computer or possibly the actuator on the transfer case even though it is moving as heard moving.

GM does have a bulletin out on some of these for the transfer case actuator sensor failing internally and confusing the computer on what gear it is selected in and their correction was to remove the transfer case motor and take it apart and replace this sensor.

You would usually have a fault code set if this is the case though.

Let me know if you need anything else,click accept if you feel satisfied with your answer as this is how I get credited for my time,Thanks Pete!
Happy Holidays!
Customer: replied 2 years ago.
thank you for all your help, plugged in another new actuator and still nothing. I am going to get this thing hooked up to a scanner and see what i can find. Do you have a part # XXXXX the 4x4 computer and where is it located? Simple to install?
Expert:  Pete replied 2 years ago.
The control module is located behind the shift switch and headlamp switch assembly,you have to remove these switches to gain access to it.The part number varies by your vehicles vin number and this control module also has to be programmed by a dealer with their scan tool and computer for it to operate properly after words.

You might check with a local parts store as they may sell these pre programmed ready for install.

It usually takes about an hour to replace it and is a tight fit inside the dash,the cluster and switches on the drivers side of the dash have to be removed in order to access and replace this module.

Let me know if you need anything else,click accept if you feel satisfied with your answer as this is how I get credited for my time,Thanks Pete!
Happy Holidays!
Customer: replied 2 years ago.

i just had my vehicle scanned. there were no fault codes and the transfer case is working properly. The front differential is not locking in like it is supposed to.

 

i think it said something like:

 

Front differential locked? (y/n) It was a NO

 

the mechanic i talked with was a gm mechanic and he seemed to think broken wire or relay.

 

We even tried unhooking the battery to reset the computer.

 

 

Do you have any input on this?

Customer: replied 2 years ago.
Thought i would let you know that i have found the culprit. I chased the main harness that goes to the transfer case, trying to find a ground. I found one mounted to the cab mount. I pushed the 4hi button and wiggled the wire and bingo the front actuator engaged. It wasnt broken or loose but i think there was some corrosion in the wire strands. I cleaned and retaped it up and now it works like a charm. All these parts and all i needed was a wire brush and some black tape.
Expert:  Pete replied 2 years ago.
Glad to hear the fault has been located and repaired.I didn't mention checking wires as in your question you had posted the wires had been checked but a loose or faulty ground connection can cause this for sure.

Let me know if you need anything else,click accept if you feel satisfied with your answer as this is how I get credited for my time,Thanks Pete!
Happy Holidays!
Pete, Auto Mechanic
Category: Chevy
Satisfied Customers: 14193
Experience: 14 years GM dealer Technician.
Pete and 11 other Chevy Specialists are ready to help you

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money. Todd L Rochester NY
< Last | Next >
  • I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money. Todd L Rochester NY
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
  • Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know. Robin Elkton, Maryland
 
 
 

Meet The Experts:

 
 
 
  • Tim's Auto Repair's Avatar

    Tim's Auto Repair

    mechanic

    Satisfied Customers:

    7497
    Have owned a repair shop for 25 yrs.
< Last | Next >
  • http://ww2.justanswer.com/uploads/TI/tim37857/2011-10-28_23053_S6301814.64x64.JPG Tim's Auto Repair's Avatar

    Tim's Auto Repair

    mechanic

    Satisfied Customers:

    7497
    Have owned a repair shop for 25 yrs.
  • http://ww2.justanswer.com/uploads/DT/dt69nova/2012-6-15_234154_pic1.64x64.jpg Dave Nova's Avatar

    Dave Nova

    Chevrolet Technician

    Satisfied Customers:

    6863
    ASE Master Certification. GM World Class Certification
  • http://ww2.justanswer.com/uploads/ggrote1/2009-06-27_031011_me.jpg Gary's Avatar

    Gary

    Chevy Technician

    Satisfied Customers:

    4944
    15 years GM master tech
  • http://ww2.justanswer.com/uploads/testedtuff/2009-09-26_170108_pictures.jpg John's Avatar

    John

    Master A.S.E Automotive technician

    Satisfied Customers:

    4071
    A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician
  • http://ww2.justanswer.com/uploads/RO/rodcuda/2011-7-25_224114_Donhoff1.64x64.JPG Neal's Avatar

    Neal

    Chevy Mechanic

    Satisfied Customers:

    2306
    Shop Owner and Mechanic on multiple makes.
  • http://ww2.justanswer.com/uploads/goodwrench9124/2008-11-09_220838_dscf0007.jpg goodwrench9124's Avatar

    goodwrench9124

    ASE Certified Technician

    Satisfied Customers:

    2041
    Ase Master Certified, GM Master Certified Tech. Awarded GM Top performer, Hybrid certified
  • http://ww2.justanswer.com/uploads/DR/drivefast1971/2012-1-12_172422_0009051tQKh.64x64.jpg Ron Z.'s Avatar

    Ron Z.

    - Chevy Tech -

    Satisfied Customers:

    1813
    18+yrs experience. State Inspector and Chevy Diagnostics