Welcome to the Corvette Forums at the Corvette Action Center!

Fans Come On Right After Car Is Started....Why?

R

RubyDropTop

Guest
Hi guys -

Can't figure this out....why would my fans come on within 5 seconds of starting my car? The motor is ice cold and the A/C is OFF, so why would this happen? :confused
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Which Fan

Or BOTH?

ANy ECM mods?


Vig!
 
R

RubyDropTop

Guest
Good Question...

All I know is that I hear at least one fan kick on right away (sorry, I'm not as mechanically inclined as some other members).

The system cycles as it should after that...fans coming on at the dreaded 228 degrees, dropping the temp to 217.

No mods to the ECM.

Any thoughts?
 
S

Steel Half-Shafts

Guest
RubyDropTop,
Is it possible your hearing the Electric Air Pump that's part of the (A.I.R.) Emission System? It usually comes on with a cold engine.
The Air pump is located up in the Front Left Corner of the engine compartment and runs for a few min. on cold starts.
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Pop the hood

Watch which fan comes on.

The relay is probably getting funky


Vig!
 
R

RubyDropTop

Guest
No, no check engine light is on.

Can you humor me...where would I find the relay for the fans? Thanks.
 
Joined
Jun 20, 2002
Messages
2,509
Location
Tallahassee, FL
Corvette
none right now :(
drivers side of the radiator housing, there are two of them mounted there (if the hood is closed, it will be between the headlight and the radiator, two small black boxes, with wires coming out of the bottom of them).... If only one fan is coming on, you can unplug them both and switch them... after the switch, if the other fan is the problem, then it is the relay.
 
R

RubyDropTop

Guest
Okay, I know exactly what you are talking about. :duh . I've looked at those 2 boxes so many times and wondered what they were.

Thanks for the guidance...greatly appreciated. :)
 
R

RubyDropTop

Guest
An afterthought - if I wanted to simply swap both of the relays out for brand new ones, is that a pretty simple task? Are they available from Mid-America, Eckler's, etc.?
 
Joined
Jun 20, 2002
Messages
2,509
Location
Tallahassee, FL
Corvette
none right now :(
probably the easiest thing you can do to your vette... just unplug them, unscrew them from the housing, and replace. Available through the big parts guys, ecklers, mid america etc. also should be able to get them through your chevy dealer... may even be cheaper through chevy since there is no shipping
 
R

RubyDropTop

Guest
One More Question...

Would a bad fan relay cause a code to be thrown? I don't have any codes, so I'm just wondering.
 
Joined
Jun 20, 2002
Messages
2,509
Location
Tallahassee, FL
Corvette
none right now :(
I don't think it has a code... I don't even think the car can tell the relay is bad... it just goes on its merry way in ignorant bliss:)
 
R

RubyDropTop

Guest
Okay, I was just wondering. It wouldn't hurt to change them out anyway. I'd be surprised if they were bad, but stranger things have happened.

Thanks for your help. :)
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
The ECM has NO WAY

To detect if the relays are ACTUALLY closing.

Typically the fan as it gets old draws more current.... and the contact points on the relay get pitted.. as they get worse the relay clicks on and draws an arc ( think spot welding) and it's JUST enough to keep the contacts together reguardless of what the coil of the relay is doing.



Vig!
 

vms4evr

Well-known member
Joined
Jul 18, 2001
Messages
466
Location
Durham, NC
Corvette
2002 Flat Black Z06
Ruby,
Before you just go replacing the relays try the simple tests the guys have mentioned. If you hear the noise in the morning at startup after the car sits all night and is cold, then there is a good chance you're hearing Air Pump doing its thing. It is noisey. When I first got my92 I thought it was the fans kicking on. It wasn't. Wait a few minutes and it goes off after the engine warms up a bit. With the hood up look at your 2 fans. If they aren't turning you'll actually see the fan blades. If they're both turning you definetely won't and you should feel the air blowing up by the radiator. If it's just one running then try as suggested. Just turn the car off and swap the connections on the 2 relays. Start her up and see if it moves to the other fan. If it does scratch 1 relay. Replace them both if you feel better about that and keep the good one as a spare. Get the relays from the dealer. I've had better luck with the TRW relays from the dealer. I've tried Autozone and the relay brand I got didn't last long.
Graham
 

Corvette Forums

Not a member of the Corvette Action Center?  Join now!  It's free!

Help support the Corvette Action Center!

Supporting Vendors

Dealers:

MacMulkin Chevrolet - The Second Largest Corvette Dealer in the Country!

Parts/Accessories:

Vetteskins

Advertise with the Corvette Action Center!

Double Your Chances!

Partners

Top Bottom