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 Jeremy Your Own Question
Jeremy
Jeremy, Certified Truck/Bus Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 2783
Experience:  ASE Med/HD Truck Technician, NATEF Diesel Engines and Electrical/Electronics Technician, EPA 608/609 HVAC Certified, Steering/Suspension and ABS/Brakes Technician
9290743
Type Your Medium and Heavy Trucks Question Here...
Jeremy is online now
A new question is answered every 9 seconds

My blower motor runs on its own when I start my truck I

Customer Question

My blower motor runs on its own when I start my truck I pulled the bunk fuse now I can work my cab controls but my ac don't kick on 2004 peterbilt 379 exhd
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Jeremy replied 1 year ago.

My name is ***** ***** I will assist you.

Which blower runs all the time? Front or rear?

When you pulled the fuse, did you leave it out? If so, when you put the fuse back in does the A/C then work properly?

I'm trying to narrow down on where to look and what to check further.

__________________________________________________________________________________________________________________________
You want a 5 star service and I want to provide a 5 star service. Please consider that I don't know your skill level as well as I can't see,
touch, smell, hear, or taste the vehicle/machine in question. Please provide as much detail as possible and I will provide as much back.

The system DOES NOT automatically give me credit from your deposit. A rating is REQUIRED. You are rating me for the information I provide,
not the website. I have no control over the site fees, site errors, category errors, or how long it took for a response for these reasons.

I am not an employee of this website, so please rate with a POSITIVE (green) rating for me to get credit for assisting you. You still pay
the website for negatives or by not rating at all. I just get nothing from that payment you made. So please rate each answer I provide.

I want you pleased with my service to you so please inform me before rating negative (red) and I will do my best to make it right. Follow
ups for same question are always free after ratings have been made.

I do have many workshop manuals, diagrams, etc that I pay to get access to out of my pocket. If one is needed, please ask and I will give
you an offer at my technician discounted cost to you for such manuals. I never charge above that cost.

Thank you for allowing me to assist you through Just Answer!

Jeremy

Customer: replied 1 year ago.
Front blower my ac clutch burn up now my ac compressor locked up now im going to replace ac unit dryer orvice but the blower quit acting up when I put a shorter belt on it to bypass the compressor so I could get home but my bunk controls don't work at all now peterbilt told me to replace the compressor and then ill have to troubleshoot from there what do you think
Expert:  Jeremy replied 1 year ago.

I agree on replacing the compressor to troubleshoot the remainder, but if the compressor burned up because the compressor stay engaged all the time, that could be bad. I would put a headlight onto the A/C circuit and shine it up to the cab. Then I would pull the A/C control panel out of the dash and look on the back of it to see if there are any wires melted on the plug which could keep the fan and compressor engaged. Also replace the blower relay and the A/C relays, just in case one is sticking and causing power to hold onto the system. Then I would troubleshoot from there.

Go HERE if you need any diagrams for your unit. Scroll down and look on the right and you will see a section for schematics. You will find all you need there. These are the exact same ones that we have in the shop.

Expert:  Jeremy replied 1 year ago.

Do you still need assistance with this?

Customer: replied 1 year ago.
No
Expert:  Jeremy replied 1 year ago.

Thank you for the reply. Have a great day!