89 Camry Cooling Fans Always Running - Help Please - Toyota Nation Forum : Toyota Car and Truck Forums

stumped · 03-26-2008, 07:58 PM

Both cooling fans started running all the time, even with the key out. If I remove either the relay or fuse (under the hood) for either fan, that fan will stop. Currently I have both fuses removed.

A friend of a friend at a Toyota dealer said it could be the 2 terminal temp sensor located on the thermostat housing. This is a V6. I disconnected & it made no difference. I also found a sensor on the engine surface that faces the radiator, but disconnecting made no difference.

I searched this forum & it appears that some other years and models have a sensor at various locations on the radiator. Does the 1989 have such a sensor? Nothing was obvious when I looked. It it hidden from view by the fan shroud or do you have to get under the car to see it?

Any suggestions would be greatly appreciated.
Thanks in advance.

TBayToyotaBoy · 03-26-2008, 08:12 PM

There is no sensor located on the radiator itself, and you were "getting warm" when you looked at the ECT (engine coolant temp) sensor. If you have a voltmeter, test the ECT sensor to see if it's within spec (www.camrystuff.com has the specs).

If I recall correctly (a friend had this problem on his V6 about ten years ago), the fans will continue running even if the ECT is unplugged...the only way to shut them off is to install a properly-functioning sensor.

atobe · 03-26-2008, 08:27 PM

your relay is stuck open and needs replacing

stumped · 03-27-2008, 12:18 AM

TBayToyotaBoy,

Thanks for the information and link. My friend's friend did mention that disconnecting the temp sensor may make the fans run. IOW an open circuit would turn them on, versus a sensor that completes the circuit & grounds the fan. And that a broken wire would also open the circuit & run the fans. I looked at the wiring as best as I could & did not see anything obvious, but just about all the wiring is in a harness. So at the moment I'm ruling out a wiring problem, but keeping an open mind this still may be the culprit.

I did check the resistance of the sensor & it measured about 4 ohms. At the time I did not know if this was normal for a cold engine. With the harness disconnected it is seeing infinite resistance, and the fans run. I also shorted the terminals on the harness & thus gave it zero resistance, and the fans still ran. I figured since neither high nor low resistance made any difference that perhaps there was another sensor that was causing the problem.

The link that you provided does list different resistances depending on temp. As it gets cooler the resistance does increase, but perhaps infinite resistance (as when disconnected) is way too high and the Cooling Fan ECU thinks something is wrong & turns on the fans. This is just a guess. I have an assortment of resistors & will jumper a few across the harness and see what happens. IOW I will make the ECU think it is reading a proper sensor. I'll let you know what happens.

Thanks again.

***CharmCityES*** · 03-27-2008, 12:24 AM

theyre electronic cooling fans and your relay is stuck open...it simply needs to be replaced

toyrolla · 03-27-2008, 02:05 PM

Correct...

If it was the temp sensor, it wouldn't be running with the car off and the key out.

I have a V6 and I need to replace my temp sensor, so for now it only runs when I turn on the car...

Mike Gerber · 03-27-2008, 02:56 PM

The ECT sensor is not your problem. The ECT sensor sends engine temperature information to the ECU (Computer) so it can adjust your fuel mixture accordingly. It has nothing to do with the cooling fans. Since you seem reluctant to go out and buy another cooling fan relay, try these simple tests. First, locate the colling fan relay. Then when the fans are on and the engine is off, simply tap on the cooling fan relay. Did the fans stop running? If so, you know that relay is bad. If not, move on to simple test number 2 for the relay. See if there is another identical relay to a non-esential item in the car. Now swap that other relay for the cooling fan relay and start the car. Then shut off the car. If the problem goes away, then you have isolated the problem to that defective cooling fan relay. Then go buy yourself a new relay and put everything back the way it was.

Mike

stumped · 03-28-2008, 03:22 PM

Both fans started to run all the time, even with the key out.

Removing Fan #1 relay stops the left fan & removing the Fan #2 relay stops the right fan. They seem to operate independently of each other. Also, removing either 30 amp fuse does the same thing as removing either relay.

The two relays are different, but I'll see if there are others that are identical in order to try a swap.

Is there some interaction between the relays where one affects the other? And therefore they both have to be in the circuit? I will tap both of them, but which relay should I be concentrating on?

stumped · 03-29-2008, 05:58 AM

I looked at the cooling fan electrical circuit diagram. It looks like both fans are fed power via the "Engine Main Relay". I'm not 100% sure which contacts on any of the relays are normally open or closed, or how the "Cooling Fan ECU" activates the relays. But it appears the Engine Main Relay only supplies power to the fan relays when the ignition is on and that is the only way the fan relays can get power. So if my fans are running, the Engine Main Relay must be stuck "on".

I pulled the Engine Main Relay while I had the 30A fuses out because it was easier to grab onto. I put back both 30A fuses then the Engine Main Relay. Now the fans are off. I'm presuming that the movement of removing the Engine Main Relay caused the stuck contacts to open. I wish I had put the fuses in before removing the relay in order to change the series of events & see what happened.

I never suspected the Engine Main Relay because of its name. I figured it must have something to do with the engine itself. I'll keep an eye on this relay. Maybe I'm going down the wrong path, but what do you think?

Kep · 03-29-2008, 10:43 AM

What were the results of the tests that Mike recommended? If you don't like those I suspect the manual shows a multimeter test that you can perform on the relays as well. Usually there are 4 terminals on the relay. Two for the on/off signal and two for the fan. Test for continuity across the fan terminals. When the on/off signal terminals have 12 volts it will be on or off and when you remove the 12 volts from the signal terminals it will be the opposite. Mike's tests are easier.

I wouldn't bother looking at something besides the relay(s) until you exonerate the relays.

Kep

stumped · 03-29-2008, 11:54 AM

The problem I have is determining which relay. As I mentioned, there is more than one cooling fan relay. And removing one relay stops one fan and removing the other relay stops the other fan.

Checking the relay is easy. I'm just trying to find the correct one. Of course after handling all the relays everything is back to normal. So I agree it must be a relay. While anything can happen, what are the odds that both fan relays went out at exactly the same time. And started working (at least for now) at exactly the same time. I am keeping an eye on the Engine Main Relay. It seems an unusual name to call it, but the schematic shows it feeding 12 volts to both cooling fan circuits. Perhaps it also suppies power to other items not shown in the fan schematic.

I do appreciate everyone's help & am not trying to be difficult. I'm just trying to narrow down the suspect relay.

Thanks again.

Kep · 03-29-2008, 03:39 PM

Well, after looking at a manual I am seeing 1) No. 1 Cooling Fan Relay (Fan No.1), 2) No. 2 Cooling Fan Relay (AC Fan No.2) 3) No. 3 Cooling Fan Relay (AC Fan No.3) 4) Fuseable link (Fan 30A), 5) Fusible Link ALT 80A (at the battery post) 6) Engine Main Relay 7) 7.5A ING Fuse (in the DS kick panel), 8) the water temp sensor 9) the two fans themselves and 10) the Cooling Fan ECU.

1-4 are in the engine compartment fuse panel next to the battery.

This is info from the "cooling" section of the manual, pg 24 of 27.

Kep

Mike Gerber · 03-29-2008, 05:55 PM

stumped,

I think that Engine Main Relay is now the prime suspect. If the problem returns try tapping on that Engine Main Relay. If the problem goes away, you have found the bad relay. If the problem remains, do you have any friends with a similiar Camry to your's or any Toyota product of a similiar generation to your's? If so, have them come over or drive over to them. Pull your Engine Main Relay and notice the Toyota numbers on it. Now pull their Engine Main Relay and see if the numbers are the same. If so, try swaping their relay in to your car for a minute and see if that solves the problem.

Mike

stumped · 03-30-2008, 06:56 PM

Quote:

Originally Posted by Mike Gerber

stumped,

I think that Engine Main Relay is now the prime suspect. If the problem returns try tapping on that Engine Main Relay. If the problem goes away, you have found the bad relay. If the problem remains, do you have any friends with a similiar Camry to your's or any Toyota product of a similiar generation to your's? If so, have them come over or drive over to them. Pull your Engine Main Relay and notice the Toyota numbers on it. Now pull their Engine Main Relay and see if the numbers are the same. If so, try swaping their relay in to your car for a minute and see if that solves the problem.

Mike

I agree about the Engine Main Relay being the prime suspect. I made several short shopping trips both yesterday & today and so far everything is normal. I even turned on the A/C and both fans kicked on. And both stopped when I turned off the A/C. This is probably the start of an intermittent problem, but at least I know where to start looking. I don't know anyone else with a similar Toyota, however I will get the numbers off my relay just in case I need to locate & buy one in a hurry. But I still wonder why it is called the Engine Main Relay.

Thanks again.

stumped · 06-29-2009, 06:21 PM

Well I have just the opposite problem than what I had last year. Instead of continually running fans, now neither fan runs.

After handling all the relays last year everything worked OK - until now. So I suspected the Engine Main Relay again. I gave it a few sharp taps & the fans ran. I pulled the plastic cover off the relay & could see it was being energized, but the contact continuity was intermittent. If I pushed on the movable contact just a little it would spark a bit, make contact & the fans would run. I burnished & cleaned the contacts which helped a bit, but it is not 100% reliable.

The Toyota dealer by me wants $52.77. The auto parts store wants $42.99. I could try a junk yard for a used part, but I'd rather go for new on this item. I did a bit of Internet searching and saw other 30 amp relays for $2 to $3. What the heck makes Toyota's relay so expensive? Anyone know of a source for inexpensive relays?