jesshaines

Hello all,

sorry if im repeating but ive read a ton of threads and can't seem to find one that fits my problem.

Cooling fan wont come on on my 2000 civic. Ive replaced switch and relays. Ive jumped it with a paperclip and it works fine, but when I turn on the key and ac, ac fan runs but not cooling. Any ideas?

The only thing I see is the wire harness that plugs into switch doesnt seem to be exactly perfect. It slides on there but comes up about 1/8 to 1/4 inch short of sliding on all the way. But, I've looked at switch and harness and eye ball measurement says theres plenty of tooth in there to get good connection.

thanks in advance!

White_EG1

Fix/replace harness

Asphalt Art

Is there a bent pin, or other debris inside the connector, preventing full engagement?

There is no other reason the connector cannot fully lock to the receptacle.

jesshaines

ShinsenTuner

iTrader: (1)

Two things could be happening:

1. Fan Switch Malfunctioned/Damaged - Remove and Replace if it is
2. Engine not reaching temperature to activate fans - Depending on the car, I want to say activation temp for the thermostat is like 170-180F. Not too long after the fans should kick on. I confirmed this by attaching my OBD2 dongle on and using the Torque app to read it. Not sure of standard OBD readers can do this.

jesshaines

yes, that sure seems logical. Unfortunately.....

I've replaced switch, it tested good in pot of water before install.
it seems to have good connection with harness.
I just ran car till temp needle reached over half way (normally runs below half) lower radiator hose had started to heat up, thermo open but no cooling fan. I wish I had obd2 for more accurate check but still, temp clearly rising significantly, and no fan. Wtf!

one other peice of info - cooling fan doesnt come on when a/c is on and ive heard that it should....so possibly some wiring fluke somewhere???? Also wondering if a somewhat corroded water pump could cause this, just not pushing enough water to get hot stuff to switch?

help!

jesshaines

This is a d16y7.....I'm running out of ideas how to get cooling fan to turn on at appropriate engine temp. Before I take the last ditch step and hardwire a toggle switch, just wondering if anyone can gelp diagnos actual cause

Fan works fine when jumped with paper clip at switch connector....
Ive replaced tstat and thermoswitch, both tested good in pot of water b4 install
bled and rebled cooling system
doesnt run when car starts to get hot (Ive run it up to about 2/3 up gauge)
doesnt run when I turn on a/c - compressor fan runs, but not cooling

I'm looking at wiring diagram, dont understand how this can be.

ive replaced relays and checked fuses, but the fact that it runs when jumped with a paperclip lead me to believe everything downstream from switch connector is fine.

no leaks I can see with visual inspection. I'm thinking of pressure testing system. Could this be caused by air getting into system somehow? But the fact it works when jumped, doesnt work when turn a/c on leads me to suspect its some problem with wiring I'm missing. Or, a corroded water pump impeller that just isnt pushing enough water - still, the lower rad hose does get hot, so some flow is happening. Help!

apologies if this isnt stated clearly ir theres something obvious I'm missing - definite noob finding my way!

thanks for any ideas!

JRCivic1

I don't believe the cooling fan comes on automatically just because you have turned the A/C on... it comes on when the cooling system requires it... which might be more often while your A/C is running. The only reason your cooling fan is not coming on would be because of an air bubble in the system OR you have a non-OE thermostat that is not allowing the proper amount of fluid to bleed over into the thermostat cover and make contact with the fan switch. You need an OBD-2 scanner to check the cooling system function at idle... I recommend you run the car until the coolant temperature reaches 208 degrees F without any fan operation to verify your issue.

1992BB2

If the fan runs when you jump the connector for the ECT switch, then that can mean three things:

1. The switch is no longer "switching" and is faulty.

2. The switch is not getting hot enough to switch on. (Which could be a clog in the coolant lines somewhere, or maybe you just aren't getting the car hot enough to engage it and it works fine.)

3. The connector that plugs into the switch isn't making full contact with one of the 2 pins.

To rule out the first two, take your multi-meter (If you don't have one, HF has cheap ones that will work just fine for this), and set it to the continuity function. While leaving the switch still installed into the housing, connect one cable of the meter to one pin on the switch, and the other cable of the meter to the other pin on the switch. When it reaches the proper temperature that your fan should kick on at, your meter should beep. If it beeps, then it's number 3. If it doesn't beep, it's either 1 or 2.

Hope this helps.

mk378

Jump the fan switch plug and test drive with fan running all the time. If it still overheats, there is a problem with the cooling system, not the fan control.

The A/C condenser fan runs with the compressor it has nothing to do with engine temperature. Unlike most cars, the radiator and condenser have separate air paths.

jesshaines

Problem resolved - I think there was still too much air in the system. I'm in the high desert of so-cal where 110 is a cool day, so when I was bleeding system before, it overheated pretty quick and even plugging fan in with temp gauge at 2/3, it didnt work. What I ended up doing was jumping fan with paperclip when it started to overheat in order to get bulk or air out. Once I had gone through a couple "cycles" like this, I plugged the fan connector back on and works like its supposed to.

I feel a little foolish, but thanks for help and clear instructions

jesshaines

yes, it seems there was too much air in the system. I'm in a hot weather area, so I ended up jumping fan with paperclip so engine wouldnt overheat while getting bulk of air out, then plugged fan in and worked like it supposed to.

Feel a little foolish :-) thanks for your help