97 accord heater woes
#1
97 accord heater woes
I have a 97 Accord LX. I have no heat, the cooling fan does not come on when the engine is running, but does when the car has been running for a while and then is shut off. The a/c works perfectly--both fans come on. I replaced the thermostat and the sensor on the thermostat housing--both to no avail. Can't be the fuses or relays--both fans come on when a/c is on. Pulled sensor on thermo housing and jumped wires, and the fan came on. Did the same on the sensor near the upper hose--fan came on, so not a wiring problem. I'd appreciate any help.
#3
Honda-Tech Member
Re: 97 accord heater woes
^ WOW, someone found their way out of GDD....what is going to happen to "tech" now
OP - need to check that the heater control valve cable is moving when you turn the **** from heat to cool and back.
Next check the temp of the hoses on both side of the valve when open (heat) and be sure the valve is opening.....they can fail internally which meands the cable moves and you think it is opening but it is not. If both hoses on the valve are getting hot also check the return to check if there might be a blockage in the heater core.
OP - need to check that the heater control valve cable is moving when you turn the **** from heat to cool and back.
Next check the temp of the hoses on both side of the valve when open (heat) and be sure the valve is opening.....they can fail internally which meands the cable moves and you think it is opening but it is not. If both hoses on the valve are getting hot also check the return to check if there might be a blockage in the heater core.
#4
Re: 97 accord heater woes
Checked both control valves--the one under the glove box and the one at the firewall. Both open and close. Just replaced the sensor near the radiator. Fan still does not come on, car still overheating, fan still coming on when engine is off, but now the engine is surging intermittently. Don't know what else to try.
#5
Honda-Tech Member
Re: 97 accord heater woes
The overheating was not brought up in the first post ?
Be sure that you bleed the air out of the cooling system, there is a bleeder on the t-stat housing.
I'd also check the compression to be sure the head gasket is ok.
Be sure that you bleed the air out of the cooling system, there is a bleeder on the t-stat housing.
I'd also check the compression to be sure the head gasket is ok.
#6
Re: 97 accord heater woes
Thanks for the reply. Changed the thermostat again, bled the coolant again, jumped the switch at thermostat and the switch at the end of the top radiator hose, and both made the fan run. The top hose gets hot, and the bottom one gets warm. Car gets to operating temperature in good time. Still no heat. Cooling fan came on once, then not again, and car started to overheat. I'm going to test the thermistor at the thermostat to see if that's why the fan doesn't run, But I'm mystified about still getting no heat. Maybe a blocked core?
#7
Honda-Tech Member
Re: 97 accord heater woes
Lets solve the overheating before we get into the heater core.
Next, might just be the wording - BOTH cooling fans should run when needed and the key is in the "on" position. So with the key on, just the wire connector to the cooling fan switch on the t-stat housing where the lower hose connects. Do BOTH cooling fans come on?
Next, might just be the wording - BOTH cooling fans should run when needed and the key is in the "on" position. So with the key on, just the wire connector to the cooling fan switch on the t-stat housing where the lower hose connects. Do BOTH cooling fans come on?
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#9
Re: 97 accord heater woes
It sounds like your fan switch is not working. Replace with a fan switch A from a Honda dealer. Don't buy aftermarket as they are junk and don't last even close to as long. The fan switch is the one that goes where the lower radiator hose goes to.
For the no heat, it could be that your thermostat is stuck open. The lower hose should get as hot as the upper hose after the car has warmed up. If not, then you need a Honda thermostat as well.
For the no heat, it could be that your thermostat is stuck open. The lower hose should get as hot as the upper hose after the car has warmed up. If not, then you need a Honda thermostat as well.
#10
Re: 97 accord heater woes
Thanks for the suggestion. I just put a Honda thermostat in, so I guessing the heat problem lies elsewhere. I am going to take the fan with out and test it in hot water to see if the resistance drops. I'm actually hoping it doesn't so at least I will have solved part of the problem.
#11
Honda-Tech Member
Re: 97 accord heater woes
Almost sounds like you have air in the system. But if you've bled properly, then sure fire way to find heater issues is to remove the air intake hose, to give you room. Then bring car to operating temp. Now check, with your hand, the two heater hoses. They should both be hot if heater valve is open. If only one is hot(the one with the valve) check make sure both sides of valve are hot. If other hoseis hot, valve hose is not. Then I'd suspect a clogged core.
#12
Re: 97 accord heater woes
Thanks for the suggestion. I just put a Honda thermostat in, so I guessing the heat problem lies elsewhere. I am going to take the fan with out and test it in hot water to see if the resistance drops. I'm actually hoping it doesn't so at least I will have solved part of the problem.
Google search "eric the car guy heater core flush"
#13
Honda-Tech Member
Re: 97 accord heater woes
Lil tip, buy these:
If youre planning on removing the heater core hoses. I can honestly say these are some of the most handy tools i have ever bought.
If youre planning on removing the heater core hoses. I can honestly say these are some of the most handy tools i have ever bought.
#14
Re: 97 accord heater woes
I don't have that set, but I have the set of three that are similar just not closed. I really could use that set but the 90 degree one kinda does the trick.
#15
Re: 97 accord heater woes
Just replaced radiator fan switch, and now the radiator fan comes on when it is supposed to. Both radiator hoses are hot at operating temperature, so the thermostat is opening. I can see both heater valves moving when I operate the heat control. Still no heat. Is it safe to assume that the problem is a blocked heater core, and, if so, what is the best way to go about unblocking it? I'll pick up those tools, to get the hoses off, but what then?
#16
Honda-Tech Member
Re: 97 accord heater woes
Never assume.......just me.
So is the car NOT over heating now? If not, lets now try to solve the heat issue.
First, just me and the way I read your post...."I can see both heater valves moving".....there is only one heater control valve ....picture of these two "said" valve will help.
So is the car NOT over heating now? If not, lets now try to solve the heat issue.
First, just me and the way I read your post...."I can see both heater valves moving".....there is only one heater control valve ....picture of these two "said" valve will help.
#17
Re: 97 accord heater woes
There's a little door under the dash near the glove box that Honda calls a heater control valve because it's actuated by the heat control dial. This dial also controls a "valve" on the heater hose going to the heater core. This is located on the engine side of the firewall. Both of these appear to be working.
#18
Honda-Tech Member
Re: 97 accord heater woes
There's a little door under the dash near the glove box that Honda calls a heater control valve because it's actuated by the heat control dial. This dial also controls a "valve" on the heater hose going to the heater core. This is located on the engine side of the firewall. Both of these appear to be working.
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05-30-2011 07:40 PM