Do I have a bad relay if my ac comes on only when i hit a bump 2010 audi a4

Asked by Jul 27, 2017 at 03:54 PM about the 2010 Audi A4

Question type: Maintenance & Repair

9 Answers

5,940

Could be anything electrical or a weak clutch magnet on your compressor. Loose connection, split wire making contact, something loose in or under fuse box. Relays do get weak and work intermittently and sometimes with a hit on them or close by. Ground wire loose? Connections to compressor all tight?

I will check all my connections Thank you

5,940

See if you have an identical relay that matches the AC relay in the box and interchange them to see if the other circuit now has issues. Many times the horn relay is the same as the AC clutch relay. MCLT is what many makers label the compressor relay.

The compressor will come on and the blower is not so then I open the hood and drop it. and the blower will work? Car has 42000 miles

5,940

Check the blower resistor on your car. Generally on passenger side in cabin by the persons feet or up a little under dash. Close to the blower that blows across evaporator. Google it for your car and location. About $30 - $40 of this is it. Also find the fuse or relay that runs this blower circuit and see if it is a bad relay, fuse or loose connection in circuit? Do a continuity test from inside cabin to fuse box location of that circuit. Also does some (not all) speeds work on this resistor? This is GENERALLY 100% proof that this resistor is bad. If this is good could be the control board on dash or wiring to this control board.

5,940

Blower motor resistor. Sorry. It is an easy replacement on most cars. If this is your issue...

Thanks I will check all connections, all speeds work fine when I take it off auto. And the Blower resistor for the Audi is $400.00 and the blower motor is $125.00 This is what has led me to believe that maybe I have a bad relay?

5,940

Bad Audi for those prices!!! On a serious note, Relays are very easy to check and are cheap online. I have even gone to a junkyard and pulled the entire box for pennies on the dollar. YouTube how to check a relay. It is easy! Pull a few (mark where they went) see if the one in question has a weaker clicking sound or has higher ohms than similiar ones. See about pin fittment is good in the box or if there are any melting or burn marks where this relay fit.

Thank you!!

Your Answer:

A4

Looking for a Used A4 in your area?

CarGurus has 669 nationwide A4 listings starting at $3,995.

Postal Code:

Audi A4 Experts

  • #1
    Deathjam4
    Reputation
    4,880
  • #2
    lukeyramone
    Reputation
    750
  • #3
    F_O_R
    Reputation
    510
View All

Related Models For Sale

Used BMW 3 Series
145 Great Deals out of 2,360 listings starting at $950
Used Audi A6
22 Great Deals out of 284 listings starting at $3,490
Used Audi A5
17 Great Deals out of 190 listings starting at $10,995
Used Audi S4
14 Great Deals out of 133 listings starting at $6,850
Used Audi A3
15 Great Deals out of 245 listings starting at $4,250
Used Mercedes-Benz C-Class
101 Great Deals out of 1,947 listings starting at $2,480
Used BMW 5 Series
33 Great Deals out of 701 listings starting at $3,200
Used Honda Accord
65 Great Deals out of 1,673 listings starting at $1,795
Used Audi Q5
23 Great Deals out of 625 listings starting at $8,900
Used Ford Mustang
51 Great Deals out of 1,604 listings starting at $1,980
Used Dodge Charger
49 Great Deals out of 932 listings starting at $3,995
Used Mercedes-Benz E-Class
33 Great Deals out of 779 listings starting at $5,499
Used Audi A8
3 Great Deals out of 56 listings starting at $8,900
Used Volkswagen Jetta
151 Great Deals out of 3,682 listings starting at $1,895

Used Cars for Sale

2018 Audi A4 For Sale
7 Great Deals out of 132 listings starting at $29,992
2017 Audi A4 For Sale
11 Great Deals out of 82 listings starting at $26,900
2016 Audi A4 For Sale
28 listings starting at $23,492
2015 Audi A4 For Sale
4 Great Deals out of 71 listings starting at $16,750
2014 Audi A4 For Sale
65 listings starting at $14,995

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.