Cooling fan issue

[Johnnytheknife]

Hi All,

Not sure which forum would be best to post this.

I'm having an issue with the fans on my 1995 NA8 (a Eunos R Limited). In stop start traffic, the engine temp is slowly creeping up from 90 degrees to I would say around 100. The car is fitted with air conditioning and I understand both fans run in tandem when the air con is turned on. I tried turning on the air conditioning but it isn't working either (just blows hot air). WHen moving anything about about 30km/h, the temp is fine.

It did this a couple of weeks ago, so I:

Tested the main cooling fan runs using the diagnostic port - fan works
Cleaned the connector to the temp sensor on the front of the motor (didn't touch the rear one)

There was still no joy with the air con starting the fans, so I reconnected the diagnostic jumper, started the motor then turned on the air conditioning. Both fans worked. I disconnected the jumper and the cooling fan and air con fan worked for about two weeks.

This afternoon it did the same thing again (temp creeping up in traffic, A/C not working). I'll test it again with the diagnostic jumper when I get a chance later on, but wondering if anyone has any ideas?

My first thought is the fan relay and/or A/C relays not working properly.

Something else of note, which could be a red herring, when I turned on the cabin fan prior to trying the A/C this afternoon, the temp gauge increased rapidly then settled around 100. It dropped immediately (but not back to 90 where is normally sits) when I turned off the cabin fan.

JtK.

[Johnnytheknife]

Ok, so I've just tried it in the driveway and the fans both work when the air con is turned on. The ac definitely wasn't working on the way home (cold air comes out now).

So it seems to be an intermittent fault (my favourite kind )

I cleaned any connections to do with the fan that I can access.


It's been idling in the driveway for about 20 minutes and I just checked, the fan is running (air con off), so aside from closely monitoring the temps, not really sure what to do next.

[Johnnytheknife]

An update to this. I installed a switch to manually activate the fan (via the existing relay) and an indicator light so I can tell if the fan is running. The indicator light runs off the main power supply to the fan, on the switched side of the relay.

I should now be able to activate the fan any time i like, bypassing any potential sensor problems. I can also verify that at least the fan relay is working. I used a ground from under the dash for the indicator light, so if the fan lost its ground connection, but the relay still switched and positive supply, the led would light even though the fan isn't running. I may end up running a gnd from the fan itself, it wouldn't be hard, but for now what I've got should at least tell me if the fan is coming in automatically, and allow me to manually control it if there is a sensors problem.