1995 Accord cooling fan/ idle problem
#22
RE: 1995 Accord cooling fan/ idle problem
There are two cooling fans. Does only one fan run? Pax (radiator) or driver (condensor) fan?
Cooling fans and compressor are linked. They have a common ground path through the pressure switch, AC switch and heater blower switch. If your AC switch is shorted to closed position (always on), then AC and fans would always run together whenever heater blower was turned to ON. Disabling one of the cooling fans (pax or drivers side) would not affect this. There are separate fuses for pax (fuse 21) and radiator (fuse 34) fans.
The compressor engagement is controlled by the ECU supplying ground to AC relay. ECU gets a ground signal from AC circuit through AC pressure switch, AC thermostat, AC switch, and blower switch. If AC switch is shorted closed, you can only turn compressor OFF by opening heater blower switch to OFF.
You need a circuit diagram and some careful diagnostics. Try downloading the 94-97 Accord manual from the Online Manuals DIY note.
good luck
Cooling fans and compressor are linked. They have a common ground path through the pressure switch, AC switch and heater blower switch. If your AC switch is shorted to closed position (always on), then AC and fans would always run together whenever heater blower was turned to ON. Disabling one of the cooling fans (pax or drivers side) would not affect this. There are separate fuses for pax (fuse 21) and radiator (fuse 34) fans.
The compressor engagement is controlled by the ECU supplying ground to AC relay. ECU gets a ground signal from AC circuit through AC pressure switch, AC thermostat, AC switch, and blower switch. If AC switch is shorted closed, you can only turn compressor OFF by opening heater blower switch to OFF.
You need a circuit diagram and some careful diagnostics. Try downloading the 94-97 Accord manual from the Online Manuals DIY note.
good luck
#23
RE: 1995 Accord cooling fan/ idle problem
Update: I took it to a local mechanic that is recommended in the area. I ran the problem by him, along with everything I have done. He took a quick (free) look at the car, and didnt know for sure. But he did say that my running temp was way too low. This was news to me since I had nothing to really compare it to, so I never thought it was an issue. It was just barely at the quarter mark on the temp guage. He said I should be at half. He also told me that there are 2 cooling temp switches, and that I only replaced one. He told me I should first start by changing out my thermostat and then go from there. He also said that might have something to do with it. So I got a new thermostat, and I also bought the other cooling temp switch. One of which runs at a higher temp. I made sure I put the right one in the right place, flushed the whole system, Installed new t-stat and gasket. Then retested. It now runs at proper temp, and seems like overall runs a little better. BUT to my high dismay it did not affect the idle drop problem at all. So Im back to where I was. With a new battery, alternator, 2 new cooling temp switches, replaced IACV, replaced FITV. And with the original problem. So my next move is "give up completely on fixing this by myself" and having a the same mechanic figure it out. Then Ill go from there. Im still convinced its a short somewhere. But Im not even goin to try to figure where. Ive had it with this problem. I havent even been able to move on to my other issues. Knock noise, ticking EGR valve, and a few more. Anywho Im done ranting. Ill definatley update when I find out what this pain of a problem is.
#24
RE: 1995 Accord cooling fan/ idle problem
All the HondAcuras Ive owned, normal operating temperature was below half. More like 1/3 to 1/2. So 1/4 is too low, but it doesnt have to be as high as 1/2.
Thenew thermostat was a good idea, but not the cooling fan switches. Heres how it works...
Theres a fan switch in the thermostat housing - that one is responsible for switching the fan while the engine is running. Say you are parked & idling or stuck in traffic...
Theres another fan switch right in the nozzle where theupper radiator hose attaches to the head. That one is responsible for switching the fan AFTER you turn OFF the engine.
You still need to be looking into why the AC compressor engages when its not supposed to.
Whether you or the mechanic gets into it, you have to keep in mind how Honda does their idle control system in those days.Its based on the ECU measuring most of the larger loads and being able to anticipate its action with the IACV. The electrical loads are measured by a device called the ELD (in the fusebox).
The AC is just about the biggest load of all. But the ECU knows when it comes on, because the ECU is part of the AC control system. It knows because the ECU creates the signal that engages the AC clutch.
If the AC engages itselfwithout this signal, that means that the ECU has NOT had a chance to anticipate the idle drop & so it didnt command the IACV todo something about it.
Thenew thermostat was a good idea, but not the cooling fan switches. Heres how it works...
Theres a fan switch in the thermostat housing - that one is responsible for switching the fan while the engine is running. Say you are parked & idling or stuck in traffic...
Theres another fan switch right in the nozzle where theupper radiator hose attaches to the head. That one is responsible for switching the fan AFTER you turn OFF the engine.
You still need to be looking into why the AC compressor engages when its not supposed to.
Whether you or the mechanic gets into it, you have to keep in mind how Honda does their idle control system in those days.Its based on the ECU measuring most of the larger loads and being able to anticipate its action with the IACV. The electrical loads are measured by a device called the ELD (in the fusebox).
The AC is just about the biggest load of all. But the ECU knows when it comes on, because the ECU is part of the AC control system. It knows because the ECU creates the signal that engages the AC clutch.
If the AC engages itselfwithout this signal, that means that the ECU has NOT had a chance to anticipate the idle drop & so it didnt command the IACV todo something about it.
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