Good to hear that one issue was solved.

 

Got voltage readings as follows: #38-10.95, #34-11.64, #21-0 (off) 0 (ignition on II) 0 - engine running, #8-0 (off) 12.0 (ignition on II) 13.87 engine running. I appreciate your help with translating this.

 

Under-hood Fuse No. 21 (20A) – should be hot at all times, no power going to radiator fan relay. Problem at under-hood fuse box if no power there at the 20A fuse. Check the electrical harness connector and wiring under the fuse box.

Under-hood Fuse No. 38 (20A) – Door lock control works; you already fix the door lock, windows, and mirror problem with the ground connection running through connector C417 (at the door jamb). -- I inadvertently listed this fuse as part of my previous post (post #8) in regards to A/C and fans.

The following have power available that goes to the following A/C related controls, and cooling fans components. Doesn’t necessarily mean power has reached that component, for example, there can still be an open (e.g., break) in the wiring or a loose connector leading to those components.
Under-hood Fuse No. 34 (15A) – power available to radiator fan control module and A/C compressor clutch relay
Under-dash Fuse No. 8 (7.5A) – power available for A/C thermostat, A/C compressor clutch relay, heater control panel

 

Thanks again for your help with this. Any suggestions on any more testing that could be done at this point? How about checking voltage readings of the compessor clutch relay and the condensor fan relay located by the side of the radiator? I recently took a reading on the compressor clutch relay resistor and it was not the reading that was called for but it did register something?

 

Not sure what you’re referring to as the A/C clutch relay resistor, as there is no A/C clutch relay resistor.

Here are some checks you can make:

1. Normally this test is to check the operation of both the radiator fan and the A/C condenser fan; however, since you’re not receiving power at the No. 21 fuse in the under-hood fuse box for the radiator fan relay, the radiator fan will not run in this test. Disconnect the 2P connector at the Engine Coolant Temperature Switch A (located on the thermostat housing, lower radiator hose); with a wire or small paper clip, jump the terminals on the harness connector side. Turn the ignition to ON or START, does the condenser fan run strongly? If the condenser fan runs strongly, the condenser fan motor, A/C condenser fan relay, and wiring is good at that portion of the circuit.
2. You could try to apply ground (-) to the Red/Blu wire at the A/C compressor clutch relay and see if the A/C clutch engages with the ignition turned ON. Only do this briefly. If it works, the A/C compressor clutch relay works and it is receiving power there.
3. If you to want to test the operation of either of the cooling fan relays or A/C compressor clutch relay (they are all 4 terminal relays) the traditional way, take them out and check for continuity between the terminals.

4 terminal relay:

• There should be continuity between the No. 1 and No. 3 terminals when power and ground are connected to the No. 2 and No. 4 terminals.
• There should be no continuity between the No. 1 and No. 3 terminals when power is disconnected.

 

Thanks for that information. I worded it wrong, should have said a/c compressor clutch field coil.. According to Alldatadiy field coil resistance should be 3.6 +/- 0.2 ohms @ 68 deg. F. I believe I got a reading about half that much but will check again when I do these other tests. Thanks again for your help.

 

It takes a semi-good meter to be accurate at a low resistance like that. The difference between 3.6 ohms and 2. ohms is probably the difference between a $150 Fluke meter vs. a $20 Autozone meter. Seems like an unusual failure that way, rather than going open-circuit, so the meter accuracy is just a suspicion of mine.

 

OK, so I jumped ECT A and both fans immediately came on full speed. No continuity between relays 1 and 2 with power disconnected on the relays. Compressor clutch won't engage with ground attached to blue/red wire. Clutch field coil reading this time does not register? Any thoughts about these readings. Thanks again for your help.

 

A1: When you jumped connector at ECT A and both fans immediately came on full speed, that means:

• The A/C condenser fan relay works.
• The radiator fan relay works.
• Unless, someone re-routed the power to radiator fan relay or radiator fan, it sounds like there is power coming through Fuse No. 21 (under-hood fuse box).
• Power, grounds, and wiring are okay for the circuit from ECT Switch A -> radiator fan control module -> relays -> cooling fans
• Does not mean ECT Switch A is good or bad. Does the car overheat, etc.?

A2: I previously wrote the relay test wrong. The test should be continuity between terminals 1 and 3 when power and ground connected to terminals 2 and 4. (I corrected my above post.)

• The relays are normally open type relays. When power and ground and connected to terminals 2 and 4, this should energize the relay, to close the relay and allow power to go terminals 1 and 3.
• No need to further test radiator fan relay and A/C condenser fan relay, as the fans worked when you jumped the ECT Switch A connector.

• You can still test the A/C Clutch relay though.

A3: For the A/C Clutch, you can do the following:

• Test the A/C clutch relay as previously noted.
• With a voltmeter, check for voltage power ( +) by touching the voltmeter red lead to the A/C Clutch relay White wire and the voltmeter black lead to chassis/metal ground to see that power is coming to the relay (White wire should be hot at all times). Then similarly check for voltage power (+) at the Blk/Yel wire (Blk/Yel wire should only have power when ignition is ON.)

A4: No comment on clutch field coil at this time.

 

Readings for a/c clutch relay: white wire 12.59, blk/yel wire 11.81 w/ ignition on. Thanks for your help with this. Checked under hood fuse #21 again and still have no reading?