My '90 Integra w/ 259K miles, is having numerous problems, and in the last week I’ve found very good info. here… so I joined.
A possible problem may exist w/ the RFCM (aka Radiator Fan Control Module)… not to mention the dreaded surging/roaming idle. so while waiting for parts on the idle problem, I’ve searched the site on radiator fan issue.
To begin, I have tried to cross-reference the location of the RFCM I found while searching alot of threads with a parts call-out (see pic below). I want to check the wiring connection because a mechanic dropped the dash (awhile back) and there is reason to believe a bad connection exists (the radio speaker wires are funky, so there you go)… then I’ll continue toward testing the Oil Temp switch and Engine Coolant Temp Switch, found here:
I would doubt the control module is to blame. I’d test the relays, motor and ECT switch first.
The unit in the diagram you posted is for the auto Trans. The RFCM is mounted on the passenger side of the heater core. Page 23-106 in your Helms manual.
I could just ID it by looking for the correct wiring plug. I asked as a 1st step, before starting diagnostics… just occupational habit, I guess.
[For the benefit of surfers / searchers]
I started at the ECT and Oil Temp switches. (1) Checked continuity of ground wire at each cable plug on both (good).
Then jumpered the Oil Temp switch, turned Ignition to ‘pwr on’ (w/out engine start) and back to ‘off’ > drivers side fan ran. Removed jumper, and (IIRC, once again, Ingition key to ‘pwr on’ (w/out engine start) and back to ‘off’ > fan stopped.
(2) W/ ingition key to ‘pwr on’, jumpered ECT cable plug > both fans ran.
[Currently, Fans have only run if & only if AC is running.]
I did not assess whether the fan timed out when I troubleshot the Oil Temp switch. when the replacement parts arrive, I’ll see what happens.
Colin, or anybody, what is the on-time period when the Oil Temp switch is working? The condition should be when engine is off & switch working (I don’t have a Helms manual yet).
[QUOTE=O Boogie;2306787]Thank You Colin !
Currently, Fans have only run if & only if AC is running.
[/QUOTE]
OK, so that sounds to me like there’s a problem with the ECT switch and should be unrelated to the oil temp switch. But I have deleted all of that BS on my car so I would need to re-read this section in the Helms to re-familiarize myself with how the control module changes things and what perimeters are used.
Yeah, ECT Switch is bad as well as Oil Temp Switch - apparently. The fans run if the AC is ‘on’ because there is a second relay involved (‘condenser relay’, wired to the Radiator Fan Control Module). I’ll know more after new ECT and Oil Switches are replaced, but I bet I’m good-to-go.
Does the RFCM have the ability to turn the fans on even if both ECT and Oil Temp switches are bad? I assumed that if they are both bad that there’s no switch to tell the fans to go on. However I’m not 100% sure how the RFCM works, there may be another switch related to the AC system. IMO it would be VERY VERY VERY strange if you both switches failed. Personally I’ve very rarely seen either fail, so both failing seems highly unlikely to me.
After a quick look-see of Helms, here’s a guess *(we’ll have to “blackbox” the RFCM, since there’s not alot, so far, that is documented -except I’ve seen it called the ‘cooling fan timing unit’ on another doc. So I’ll assume it does timing functions more than anything else).
1st, put aside the Oil Temp switch… it is on a circuitry which is, even though connected to an input of the RFCM, there is nothing that I can see which indicates its tied to the ECT, the fan relay nor the A/C condenser relay. So apparently, the RFCM just times the ‘Fan On’ condition when the oil temp is > 226 F (ie Oil Temp Sw closed). and the engine is off.
Oh, I found the ‘Fan On’ time. It should be 15 minutes.
Now with the ECT switch, it gets interesting (and w/ regard to the A/C system). 1. It is not directly connected to the RFCM, and it is a normally open Switch (as is the Oil Temp Sw)… when closed (@ coolant Temp > 194 degrees) it directly supplies ground to the fan relay and fan activates. 2. It is also connected to one side of the A/C condenser relay (which also turns on the condenser fan) in such a way that if the A/C is on, then both fans should operate (that is - the ECT is bypassed if the A/C is on…the condenser relay is controlling both the fans). So, yes, if both ECT and Oil Temp are bad the fans can run through the A/C condenser relay, together w/ the RFCM, but not sure what part the RFCM plays.
Now the condenser relay IS connected the RFCM. Here the ‘Blackbox’ analysis begins. I’m thinking that the The RFCM starts to time the fans, under this condition: A/C has been running, then turned off (& engine is running). In this event, the RFCM (perhaps?) takes over and allows the fans to run a little longer for enhanced cooling… And it seems the RFCM activates the Radiator fan as well, when A/C is on (there no other means to have both fans running wwhen A/C is on) seems to be a good guess on my part, but haven’t seen anything documented.
