The diagram shows how to properly test the ECT switch.

What did you use as ground to measure voltage at the switch socket? You may not have had good ground.

What were the wire colors in the 4P connector and which triggered the A/C to run?

 

1) OK, I didn't test it in a pot of water. I DID measure the resistance across the pins with the car pretty cool, Temp gauge was almost bottomed out, so according to that I'm pretty certain it was cool enough for the switch to be "off". I then drove fairly hard (to get the engine temp high) for a few miles to the shop and tested the resistance the same way. I will test again and let you know. I did however measure the voltage across the harness/socket pin to pin. I will ensure a solid ground to the engine or a ground strap, double check the voltage, and re-post. I will also see if I can rig a way to boil some water at the shop to test the ETC switch. If I bought a dud and have been trying to figure out a problem that's not there I'm gonna be a little ticked at myself!

2) I will also double check the harness/wire coloring for the AC. However, what I DID notice is that if I had the AC going (using the ground trigger), turning the dash AC switch on and off would NOT turn the AC itself off. (Just thought of something. Would that have to do with having the jumper across the ETC socket?)

Ron, thanks for the help. The AC would be nice to have too, but if they're not related then I'll get the cooling fan situation working 100% first. However if they ARE related, I guess I'll have to figure BOTH out!.

OK, gonna download a manual and head to the shop later this morning to see what I can find. While I'm at it I'm going to double check all fuses both under dash and under hood with a test light, just to be sure I didn't miss something there.

 

On a 97, the A/C is not related to the radiator fan at all. The systems are completely independent because the condenser has its own fan and air path that doesn't go through the radiator.

Be careful jumping stuff related to the A/C, it is possible to cause a dangerous overpressure situation if you have bypassed the pressure switch. Running the compressor without the condenser fan will cause the pressure to rise to where the hose or the relief valve will blow if the switch doesn't catch it.

 

OK tested the ETC. Cold, there is no continuity. Put a pot of water on to boil, and just before full boil I got continuity. (No I didn't have a thermometer to check water temp). So that works.

Thermostat also opens just before boil (as a 95 degree stat should) so that checks out.

I swapped out a few "iffy" looking fuses, one of which had slightly melted the plastic, but had NOT blown (10amp).

So now, the rad fan DOES come on. However once its fully warmed up, at idle, it will still display symptoms of overheating, most notably sluggish/bogging when slowly reving up (as if you were easing away from a stop). Note theat the dash gauge does NOT ever climb above its "normal" point, which is just under halfway up. I think picking up a cooler stat (185?) will open sooner, allowing the coolant to enter the rad. Not sure how I can get the rad fan to come on sooner.

One other thing I did find is that by swapping relays around, I was reading anywhere from 6.5v to 8.2v at the ETC pigtail. I assume (not sure though) this should be 12v

EDIT: could there be something else in the cooling fan circuit that I've missed that could help trigger the fan to come on sooner? I know the shop I work at has OBDII scanner, but was told it wouldn't work on a Honda. I tried it anyway, checked for codes, and got only something to do with the cat. (which I've known about already).


RonJ, if you read through this, I also checked on that AC wire. It was blue with a white tracer. By grounding this, I can trigger the AC to come on - regardless of interior fan speed or AC switch position. If I leave it run like this, the vents start blowing cooler air (not ice cold, but quite cool) and after 5 min or so the cabin temp feels cooler as well. So the freon/AC charge appears to be ok, but thats about all I know about AC.

 

bump?

 

You are likely grounding the Blu/Wht wire that runs between the condenser fan relay and the A/C thermostat in the evaporator. If you reconnect this wire, the A/C will likely work.

 

as far as I know the connections are fine. I was probing that harness to see if I had power anywhere. If I ground this wire with a test light the AC runs regardless if the dash switch is on or off, or if the interior fan switch is off, or in positions 1-4. is it possibly a bad connection within the harness?

As well (going back to the cooling fan issue) I hope a cooler 'stat will solve the problem completely. Thanks so much for your help so far

 

The A/C switch works by providing ground to the ECU, which in turn provides ground to the compressor clutch relay. If all wires are properly hooked up, then your A/C problem is caused by either a bad A/C thermostat in the evaporator, a bad heater control panel, or a bad wire somewhere between the condenser fan and heater control panel. A multimeter would help you pinpoint the problem pretty quickly.

 

ok, thanks for the advice. I've downloaded a wiring diagram for my car and also got a multimeter now. I'll start poking around and see what I can come up with. Any advice on what is most likely, or the easiest place to start checking? The light on the AC switch does come on, but does not trigger the AC.

 

The light on the button doesn't mean much, it's a separate circuit. I think the 97 was the last year with the "dumb" controls (no computer in the control panel). In that case, control panel (fan switch and A/C button) grounds the input wire to the thermostat, which should pass through to the output wire to start the condenser fan and compressor. The thermostat is mounted on top of the evaporator box, you can see it by removing the glove compartment from the dash.