Hello fellow maxima ownwers.

I am having a problem with my heat. For some reason I cannot get any kind of heat out of the vents, the blower and A/C both work GREAT, but no heat. I just did a total cooling system flush, replaced all hoses, replaces the thermostat, andchecked for leaks. I am not real familiar with heater coils, nor do I know where it is. Could it be bad? How would I know? Don't they leak if they are bad? Where is it? Any suggestions would help immensly. I want to get this fixed BEFORE I need it. Thank you in advance.

 

Sounds like you need a new heater core.........

 

You might want to check the valve that opens/closes to allow coolant into the heator core. Also you might want to check your temperature control on the dash. You want to make 100% sure you know it's the heator core before replacing it. It's expensive and a ***** to replace.

 

I checked the temp slider to make sure it was operable, and it seems to do its job. Where is the valve that opens and closes? Under the dash? Is that the cable that the hot/cold slider is pulling? If so it is turning the switch under the dash. Where is the heater core? Thanks guys.

PS. How do I get out of LURKER status? I will be here often now that I have found you.

 

I believe there is a valve on the underside of the firewall. The heator core is direcly behind the dash controls. Very hard to get to. The ENTIRE dash and support MUST come off to replace it. $1000 to do from a dealer. YOu might want to manually slide the temp control from under the dash to see if you can get some hot water into the heator core.

 

I had the same problem and my cause was a broken plastic tab right behind the plastic slider for hot/cold. It was a while ago that I fixed it so the details are a bit fuzzy, but if you look up under the dash with a flashlight from the passenger side you should be able to see the black cable with the metal wire in it coming from the general area of the heater control. It should go over to the heater core and attach to a bent rod coming out of the heater core case. When moved that rod controls flow through the heater core. If you move the hot/cold control and nothing is moving from the other end of the black cable then I would pull the heater control and check the back of it. To get the heater control out I think it was basically the same as getting the radio out with a couple extra screws. Hope this helps.

Mike

 

I replaced the heater core on an 89 se. Sort of a ***** but time and patients go a long way. And watch out, it those babys start leaking, the rist place the water goes is over the ecu plug and 12v and antifreze dont mix. the image of a ecu with a hole the size of your little inger comes to mind

 

Wow. I am having a similar problem. In fact, I was coming to the board to ask this same question. Where is that little valve? ANd what is it called? I think I had a diagnostic done this summer, and they said that it could be the problem, but they were not sure.

 

There should be a small metal rod coming out of the heater core plastic housing which is under the dash against the firewall. The metal rod is slightly larger than the diameter of a metal coat hanger. it comes out vertically from the housing and then in less than an inch or so it makes a 90 degree turn, then a short distance later makes another 90 degree turn to be vertical once again. The black plastic tube (about 1/4") coming from the heater control has a flexible, yet solid, metal cable coming from it and it should be this cable that connects to the end of the rod from the heater core housing. When the heater control is slid, the metal cable retracts or extends in the tube and the heater core housing rod is moved and in turn opens or closes the valve for the heater core. If you look around under the passenger side dash towards the middle against the firewall this should all become clear...I think. If you cant find it let me know and I will check mine to get a more accurate location, but I think it should be easy to find once you look under there. A flashlight might be good to have.
Mike

 

Thank you all very much for your input. I found the problem. It seems the switch in the engine compartment (mounted to the firewall) wasn't doing it's job. The way I found this out was I pulled on each of the vaccuum hoses individualy that attatch to this switch to make sure of proper suction. Come to find out there was one not pulling pressure. I pulled it off so the switch would flip manualy, drove the car for about an hour (to get the air out of the heater core) and wala HOT HOT air. Now I just need to get the switch replaced, but I have heat in the meantime. TRhank you all again for the helpful suggestions. This is the MOST helpful forum I have ever been to and I for one intend to stay.

 

Can you give me detailed explaination of where these hoses are, and how you tested them?

 

I'll give you what I can from here (work) and get detailed when I can get under th hood for you. This switch I am talking about is located on the firewall in the engine compartment. It is in plain sight toward the top of the engine compartment in the center. There are a couple of metal tubes running into the firewall below this switch. I believe there are three vaccuum hoses attached to the (i'm calling it a switch)and there is a small lever on the bottom of it. When you remove the vacuum lines (one at a time) one of them will release pressure to this lever. When you see the lever move over you know you have the right one. Leave that hose ONLY off and drive the car around for 10-15 minutes, and you will notice warm air start coming in on and off. Also don't worry about an initial coolant type smell it's just the heater core filling back up. Eventually all of the air should be out of the heater core and HOT heat will be consistant.

Hope this helps and is your problem too (easy fix)