91 Accord SE w/Overheating Problems
03-20-2007, 09:18 PM
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91 Accord SE w/Overheating Problems
I have a 91 Accord SE with 142k miles that I bought off of eBay a couple of weeks ago and it has some problems that I'm trying to fix. First and foremost, the thermostat had been taken out of it so I replaced that to allow it to warm up on the highways; however, shortly after replacing that I noticed that it started showing hotter and hotter on the temp gauge when I would start to decelerate or drive within the city. Upon troubleshooting the reason, I found that my primary cooling fan on the passenger side would not run at all until the vehicle was shut off, but when I turn on the AC, both fans will run without a problem.
The coolant has been flushed and is completely full and I tested the temp switch on the thermostat housing by bridging the two wires with a metal hair clip while the ignition was on but not running, but to my surprise, this didn't activate the cooling fan. What does this mean? Is there a cooling fan timer relay on this particular year or is it run by the ECU? I'm guessing this is the same problem the previous owner had and ended up just taking the thermostat out of it to keep it from overheating. Also, I've checked all of the fuses, both inside the vehicle and under the hood and pulled the cooling fan relay located in the fuse box and smelled of it and it doesn't smell burnt or blown so I need some help. I sure don't want to start parts replacing without having it narrowed down to a couple of particular parts.
Also, both of the automatic seat belts do not work and I can't find anything wrong with them. Does anyone have any suggestions for fixing these? Is it true that if I take it to a Honda Dealership, they will fix it for free since it is a safety issue and supposedly Honda gaurantees their seatbelts for life....or so I've heard. Any help will be greatly appreciated. Thanks!
The coolant has been flushed and is completely full and I tested the temp switch on the thermostat housing by bridging the two wires with a metal hair clip while the ignition was on but not running, but to my surprise, this didn't activate the cooling fan. What does this mean? Is there a cooling fan timer relay on this particular year or is it run by the ECU? I'm guessing this is the same problem the previous owner had and ended up just taking the thermostat out of it to keep it from overheating. Also, I've checked all of the fuses, both inside the vehicle and under the hood and pulled the cooling fan relay located in the fuse box and smelled of it and it doesn't smell burnt or blown so I need some help. I sure don't want to start parts replacing without having it narrowed down to a couple of particular parts.
Also, both of the automatic seat belts do not work and I can't find anything wrong with them. Does anyone have any suggestions for fixing these? Is it true that if I take it to a Honda Dealership, they will fix it for free since it is a safety issue and supposedly Honda gaurantees their seatbelts for life....or so I've heard. Any help will be greatly appreciated. Thanks!
03-21-2007, 05:00 AM
#2
Re: 91 Accord SE w/Overheating Problems (tdhull)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tdhull »</TD></TR><TR><TD CLASS="quote">I have a 91 Accord SE...</TD></TR></TABLE>Thanks for saying that - lots of people want help but don't say what kind of car they have.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tdhull »</TD></TR><TR><TD CLASS="quote">... when I turn on the AC, both fans will run without a problem.</TD></TR></TABLE>So your fan motors, their fuses & relays are OK.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tdhull »</TD></TR><TR><TD CLASS="quote">... I tested the temp switch on the thermostat housing by bridging the two wires with a metal hair clip while the ignition was on but not running, but to my surprise, this didn't activate the cooling fan. What does this mean?</TD></TR></TABLE>FIRST, try it again with a paperclip. Sometimes hairclips have a plastic coating so they don't make contact??? Try it while the engine is actually running, but I really don't think that should make any difference.
Then, that means there's a break in the wiring from that switch over to the fan timer module. I hope someone comes here & says where that fan timer module is located. (The fact that your fan runs after shutdown, seems to indicate that the fan timer module is OK.)
There's 2 fan switches and a timer module (for your year). The fan switch on the T-stat housing is responsible for switching the fan while the engine is running. The fan switch on the upper radiator hose nozzle is responsible after shutdown. The timer module is responsible for the logic of deciding which switch to use & which fan(s) to run. Timer module is also responsible for turning OFF the fan after ?? minutes even if the fan switch is stuck.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tdhull »</TD></TR><TR><TD CLASS="quote">... Is it true that if I take it to a Honda Dealership, they will fix it for free since it is a safety issue and supposedly Honda gaurantees their seatbelts for life...</TD></TR></TABLE>YES. Unless they can show that it was caused by something YOU (or prior owner) did. Like taking apart the seatbelt motors & forgetting how to put them back together.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tdhull »</TD></TR><TR><TD CLASS="quote">... when I turn on the AC, both fans will run without a problem.</TD></TR></TABLE>So your fan motors, their fuses & relays are OK.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tdhull »</TD></TR><TR><TD CLASS="quote">... I tested the temp switch on the thermostat housing by bridging the two wires with a metal hair clip while the ignition was on but not running, but to my surprise, this didn't activate the cooling fan. What does this mean?</TD></TR></TABLE>FIRST, try it again with a paperclip. Sometimes hairclips have a plastic coating so they don't make contact??? Try it while the engine is actually running, but I really don't think that should make any difference.
Then, that means there's a break in the wiring from that switch over to the fan timer module. I hope someone comes here & says where that fan timer module is located. (The fact that your fan runs after shutdown, seems to indicate that the fan timer module is OK.)
There's 2 fan switches and a timer module (for your year). The fan switch on the T-stat housing is responsible for switching the fan while the engine is running. The fan switch on the upper radiator hose nozzle is responsible after shutdown. The timer module is responsible for the logic of deciding which switch to use & which fan(s) to run. Timer module is also responsible for turning OFF the fan after ?? minutes even if the fan switch is stuck.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tdhull »</TD></TR><TR><TD CLASS="quote">... Is it true that if I take it to a Honda Dealership, they will fix it for free since it is a safety issue and supposedly Honda gaurantees their seatbelts for life...</TD></TR></TABLE>YES. Unless they can show that it was caused by something YOU (or prior owner) did. Like taking apart the seatbelt motors & forgetting how to put them back together.
03-21-2007, 02:39 PM
#3
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Re: 91 Accord SE w/Overheating Problems (tdhull)
This might help you;
http://members.troublecodes.ne...r.jpg
And also a 'block' schematic
http://members.troublecodes.ne...h.jpg
The temp switch in the line with the upper radiator hose is the one that turns on the fans when the car is off, sounds like yours is bad.
The seat belt deal is this; If the retractor is stuck in the Forward position, it qualifys.
I saw a service manager lose his job over trying to charge a customer for the repair because he claimed that the electrical parts aren't covered by the liftime warranty; if you have any problems, call american honda customer service.
http://members.troublecodes.ne...r.jpg
And also a 'block' schematic
http://members.troublecodes.ne...h.jpg
The temp switch in the line with the upper radiator hose is the one that turns on the fans when the car is off, sounds like yours is bad.
The seat belt deal is this; If the retractor is stuck in the Forward position, it qualifys.
I saw a service manager lose his job over trying to charge a customer for the repair because he claimed that the electrical parts aren't covered by the liftime warranty; if you have any problems, call american honda customer service.
03-21-2007, 03:21 PM
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Re: 91 Accord SE w/Overheating Problems (hondadude)
First of all, thanks for the help guys, I really appreciate it.
Today I tried the paperclip method instead of the hairclip but unfortunately it had the same outcome. I tried it with the ignition switch on and the car not running and then I tried with the car running and even waited until it warmed up to operating temp. Speaking of which, it never gets above operating temperature while it's idling. It's only when I begin to drive it that it starts to climb but when I run at a higher RPM, it cools back down to operating temp but when I slow down or stop, that's when it starts to climb and I've even had it up in the red, on the gauge. It seems like the only way I can get that cooling fan to come on is to turn the A/C on. Even when the AC is off and I run the heater on full blast, it won't overheat but when I leave it to it's own devices, the temp will climb and keep on climbing until I shut it off or turn on the AC or heater. What's the next step?
Thanks again for the advice.
Today I tried the paperclip method instead of the hairclip but unfortunately it had the same outcome. I tried it with the ignition switch on and the car not running and then I tried with the car running and even waited until it warmed up to operating temp. Speaking of which, it never gets above operating temperature while it's idling. It's only when I begin to drive it that it starts to climb but when I run at a higher RPM, it cools back down to operating temp but when I slow down or stop, that's when it starts to climb and I've even had it up in the red, on the gauge. It seems like the only way I can get that cooling fan to come on is to turn the A/C on. Even when the AC is off and I run the heater on full blast, it won't overheat but when I leave it to it's own devices, the temp will climb and keep on climbing until I shut it off or turn on the AC or heater. What's the next step?
Thanks again for the advice.
03-21-2007, 08:05 PM
#5
Re: 91 Accord SE w/Overheating Problems (hondadude)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondadude »</TD></TR><TR><TD CLASS="quote">The temp switch in the line with the upper radiator hose is the one that turns on the fans when the car is off, sounds like yours is bad.</TD></TR></TABLE>I think he says the only time it DOES work is when he shuts off the engine.
The wiring drawing you linked shows only one fan switch; parts drawing shows that it IS in the upper radiator hose nozzle. So it looks like the fan timer will run the fan after shutdown regardless of temperature. (Since there is no 2nd switch)
And the ECT sensor is in the thermostat housing? It's beginning to look like Honda changed that control scheme every single year??
So...
I think I steered you wrong. The fan switch (#15) is in the upper radiator hose, not the thermostat housing. Jumper the plug for THAT one, see if that turns on the fan. If so, that's the switch you need to replace.
The wiring drawing you linked shows only one fan switch; parts drawing shows that it IS in the upper radiator hose nozzle. So it looks like the fan timer will run the fan after shutdown regardless of temperature. (Since there is no 2nd switch)
And the ECT sensor is in the thermostat housing? It's beginning to look like Honda changed that control scheme every single year??
So...
I think I steered you wrong. The fan switch (#15) is in the upper radiator hose, not the thermostat housing. Jumper the plug for THAT one, see if that turns on the fan. If so, that's the switch you need to replace.
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