94 Civic AC switch pinout?
A customer brought in a 94 Civic with an AC concern. The system is tight
and charged but the compressor won't engage. I was able to check the system back to the AC relay and found that whatever grounds the relay...doesn't. I don't have a wiring diagram, Is there anything between the coil ground pin of the relay and the switch on the instrument panel? I suspect the switch. If I had the pinout for the switch I can troubleshoot from there. Can anyone provide this information? IIRC there are 5 pins on the switch. I've got 1 pin with switched power and 1 ground for sure. I imagine 1 is for the illumination of the switch. That leaves 2 unknown terminals.Any input would be appreciated. Thanks, Tom |
Re: 94 Civic AC switch pinout?
remove wrote: > relay...doesn't. I don't have a wiring diagram, Is there anything > between the coil ground pin of the relay and the switch on the > instrument panel? Yes. The relay coil ground pin is connected to the ECU. When the ECU gets a request for A/C, it will delay turning on the relay while it enriches the air/fuel mixture a bit. The A/C request comes to the ECU through the A/C pressure switch, the A/C thermostat at the evaporator, the A/C main switch and the ventilation fan switch. > Isuspect the switch. If I had the pinout for the > switch I can troubleshoot from there. Can anyone provide this > information? IIRC there are 5 pins on the switch. That's a lot of pins, don't recall it having that many. Are you sure this is an OEM Honda A/C? I once had a Civic where the dealer had installed an after-market A/C. > I've got 1 pin with > switched power and 1 ground for sure. I imagine 1 is for the > illumination of the switch. That leaves 2 unknown terminals.Any input > would be appreciated. > Thanks, Tom You can find the wiring diagram at http://www.honda.co.uk/owner/civicmanual/pdf/22-6.pdf. This wiring diagram is for the European Civic, but it is identical to the US version with three minor exceptions: 1. Ground for the condenser fan goes to ground location G751 (EU: 701) 2. Thermal protector for the compressor is shown as a separate item in the above referenced schematic. In the US schematic it is not shown, but it is still installed in the car (internal to the compressor) 3. The A/C on indicator in the EU schematic is shown as a simple light bulb. In the US variety it is shown as an LED connected through a dimming circuit. I have compared the above referenced .pdf with the wiring diagram in the Helm manual for my '94 Civic, and find only the above mentioned discrepancies. Wire colors, fuse numbers and ratings etc. match. A couple of trouble shooting tips: If the A/C-on indicator does not turn on, the problem is in the A/C main switch, or, more likely, in the ventilation fan switch. If the condenser fan comes on but the compressor does not, the most likely problem is the A/C pressure switch. It could be a faulty pressure switch, or improper pressure in the system. I do not know if this is a high pressure lockout or a low pressure lockout. I have seen both on various cars. |
Re: 94 Civic AC switch pinout?
remove wrote: > relay...doesn't. I don't have a wiring diagram, Is there anything > between the coil ground pin of the relay and the switch on the > instrument panel? Yes. The relay coil ground pin is connected to the ECU. When the ECU gets a request for A/C, it will delay turning on the relay while it enriches the air/fuel mixture a bit. The A/C request comes to the ECU through the A/C pressure switch, the A/C thermostat at the evaporator, the A/C main switch and the ventilation fan switch. > Isuspect the switch. If I had the pinout for the > switch I can troubleshoot from there. Can anyone provide this > information? IIRC there are 5 pins on the switch. That's a lot of pins, don't recall it having that many. Are you sure this is an OEM Honda A/C? I once had a Civic where the dealer had installed an after-market A/C. > I've got 1 pin with > switched power and 1 ground for sure. I imagine 1 is for the > illumination of the switch. That leaves 2 unknown terminals.Any input > would be appreciated. > Thanks, Tom You can find the wiring diagram at http://www.honda.co.uk/owner/civicmanual/pdf/22-6.pdf. This wiring diagram is for the European Civic, but it is identical to the US version with three minor exceptions: 1. Ground for the condenser fan goes to ground location G751 (EU: 701) 2. Thermal protector for the compressor is shown as a separate item in the above referenced schematic. In the US schematic it is not shown, but it is still installed in the car (internal to the compressor) 3. The A/C on indicator in the EU schematic is shown as a simple light bulb. In the US variety it is shown as an LED connected through a dimming circuit. I have compared the above referenced .pdf with the wiring diagram in the Helm manual for my '94 Civic, and find only the above mentioned discrepancies. Wire colors, fuse numbers and ratings etc. match. A couple of trouble shooting tips: If the A/C-on indicator does not turn on, the problem is in the A/C main switch, or, more likely, in the ventilation fan switch. If the condenser fan comes on but the compressor does not, the most likely problem is the A/C pressure switch. It could be a faulty pressure switch, or improper pressure in the system. I do not know if this is a high pressure lockout or a low pressure lockout. I have seen both on various cars. |
Re: 94 Civic AC switch pinout?
Randolph wrote:
> remove wrote: > > >>relay...doesn't. I don't have a wiring diagram, Is there anything >>between the coil ground pin of the relay and the switch on the >>instrument panel? > > > Yes. The relay coil ground pin is connected to the ECU. When the ECU > gets a request for A/C, it will delay turning on the relay while it > enriches the air/fuel mixture a bit. The A/C request comes to the ECU > through the A/C pressure switch, the A/C thermostat at the evaporator, > the A/C main switch and the ventilation fan switch. > > >>Isuspect the switch. If I had the pinout for the >>switch I can troubleshoot from there. Can anyone provide this >>information? IIRC there are 5 pins on the switch. > > > That's a lot of pins, don't recall it having that many. Are you sure > this is an OEM Honda A/C? I once had a Civic where the dealer had > installed an after-market A/C. > > >>I've got 1 pin with >>switched power and 1 ground for sure. I imagine 1 is for the >>illumination of the switch. That leaves 2 unknown terminals.Any input >>would be appreciated. >> Thanks, Tom > > > You can find the wiring diagram at > http://www.honda.co.uk/owner/civicmanual/pdf/22-6.pdf. This wiring > diagram is for the European Civic, but it is identical to the US version > with three minor exceptions: > > 1. Ground for the condenser fan goes to ground location G751 (EU: 701) > > 2. Thermal protector for the compressor is shown as a separate item in > the above referenced schematic. In the US schematic it is not shown, but > it is still installed in the car (internal to the compressor) > > 3. The A/C on indicator in the EU schematic is shown as a simple light > bulb. In the US variety it is shown as an LED connected through a > dimming circuit. > > I have compared the above referenced .pdf with the wiring diagram in the > Helm manual for my '94 Civic, and find only the above mentioned > discrepancies. Wire colors, fuse numbers and ratings etc. match. > > A couple of trouble shooting tips: If the A/C-on indicator does not turn > on, the problem is in the A/C main switch, or, more likely, in the > ventilation fan switch. > > If the condenser fan comes on but the compressor does not, the most > likely problem is the A/C pressure switch. It could be a faulty pressure > switch, or improper pressure in the system. I do not know if this is a > high pressure lockout or a low pressure lockout. I have seen both on > various cars. Hey, Thank you very much. That is exactly what I needed. The AC switch was indeed defective. |
Re: 94 Civic AC switch pinout?
Randolph wrote:
> remove wrote: > > >>relay...doesn't. I don't have a wiring diagram, Is there anything >>between the coil ground pin of the relay and the switch on the >>instrument panel? > > > Yes. The relay coil ground pin is connected to the ECU. When the ECU > gets a request for A/C, it will delay turning on the relay while it > enriches the air/fuel mixture a bit. The A/C request comes to the ECU > through the A/C pressure switch, the A/C thermostat at the evaporator, > the A/C main switch and the ventilation fan switch. > > >>Isuspect the switch. If I had the pinout for the >>switch I can troubleshoot from there. Can anyone provide this >>information? IIRC there are 5 pins on the switch. > > > That's a lot of pins, don't recall it having that many. Are you sure > this is an OEM Honda A/C? I once had a Civic where the dealer had > installed an after-market A/C. > > >>I've got 1 pin with >>switched power and 1 ground for sure. I imagine 1 is for the >>illumination of the switch. That leaves 2 unknown terminals.Any input >>would be appreciated. >> Thanks, Tom > > > You can find the wiring diagram at > http://www.honda.co.uk/owner/civicmanual/pdf/22-6.pdf. This wiring > diagram is for the European Civic, but it is identical to the US version > with three minor exceptions: > > 1. Ground for the condenser fan goes to ground location G751 (EU: 701) > > 2. Thermal protector for the compressor is shown as a separate item in > the above referenced schematic. In the US schematic it is not shown, but > it is still installed in the car (internal to the compressor) > > 3. The A/C on indicator in the EU schematic is shown as a simple light > bulb. In the US variety it is shown as an LED connected through a > dimming circuit. > > I have compared the above referenced .pdf with the wiring diagram in the > Helm manual for my '94 Civic, and find only the above mentioned > discrepancies. Wire colors, fuse numbers and ratings etc. match. > > A couple of trouble shooting tips: If the A/C-on indicator does not turn > on, the problem is in the A/C main switch, or, more likely, in the > ventilation fan switch. > > If the condenser fan comes on but the compressor does not, the most > likely problem is the A/C pressure switch. It could be a faulty pressure > switch, or improper pressure in the system. I do not know if this is a > high pressure lockout or a low pressure lockout. I have seen both on > various cars. Hey, Thank you very much. That is exactly what I needed. The AC switch was indeed defective. |
All times are GMT -4. The time now is 09:17 PM. |
© 2024 MH Sub I, LLC dba Internet Brands