Heater control problem

My theory is to trade the car before such things happen.

J.

Even if you planned to move overseas in a couple years?

The 90's ended for me some time ago.

J.

Unfortunately, so did Honda's engineering superiority.

i can't recall if i had to take the whole dash out just to fix this or the instrument cluster as well, but with my 96 accord, i replaced the cable, reattached the controls, and it worked again. yes, it's a pita and apparently a common problem - i suspect the cable housing is some below-spec material that gets sticky when hot and starts to seize the cable inner.

From some of the Internet posts that I saw it appeared that only the instrument panel had to be removed, but it wasn't quite clear. I agree that the sticky cable must be at fault, though there are really two separate cables there: the shorter air mix cable that is operated by the temp control dial, and the longer heater valve cable that goes through the fire wall and activates the coolant valve. This latter valve seems to be attached fine to the valve arm, so I'm not sure which cable is damaged, and what worries me even more is whether anything else is damaged or broken by the forced turning of the temp control dial before that dial went totally free-turning.

I don't want to take that instrument panel out and then only to find out that something else is broken beside a cable and having no quick way to get hold of a new part to replace the broken part. There are some plastic parts there that could be broken, I think.

Right now I just manually turned the heater valve to close position till the colder weather comes in. Then I'll just open that valve to let hot coolant flow in the heater core. Maybe the redirection of air flow into the air vents is still working by activating the various buttons on the heater control, though I'm not sure the heater door can still be operated. If not, I just hope it is open, so the blower can direct the air through the core.

it might be disconnected rather than broken. iirc, mine had done that when the cable stuck and the previous owner had tried to crank it anyway, but the mechanism, while plastic, was still quite strong.

classic work-around.

don't know if there's another way to access, but if there is, i bet it involves painful contortions. i just removed the panel to access the control cables. it's not too complicated.

for diagnosis, i disconnected the cable at the heater valve end and discovered the cable was not movable. suggest you check that out before ordering any parts, just to be sure. the airflow cable can be observed moving under the dash, so you can see if that's a problem, no disassembly required.

if you remove the panel, and your vehicle is the automatic, consider progressing to and removing the speedo cluster. the "drive" indicator bulb on the selector panel goes round about now and you can replace it while you've got everything apart. better yet, replace it with an led - utterly retarded to have a 1000 hour bulb in a 3000+ hour location.

Painful contortions are out of question for my bad back. Replacing the main realy under the dash was bad enough. :-(

I disconnected it once and it seemed to be also unmovable with the moderate amount of force I could apply there at that tight space. But I don't understand how that could tell me anything about needing to buy a new part or not. Could you elaborate?

I might first get one of those fiberoptic scopes to make checking that out easier. I've seen some fairly inexpensive models out there by Googling around. Such a flex scope can be useful for many tight space applications.

Thanks. The logic sounds the same as replacing the water pump with the timing belt. Are LED replacement bulbs readily available with the same specs?

How about disconnecting the two cables and blasting release oil up inside the cable cores. You might be lucky.

Al Moodie.

if the cable's seized internally, not only will the heater valve not operate, but the controls will disconnect themselves if forced. thus the way to get it all working again is to replace the cable and reconnect it all. iirc, part of the plastic outer on mine had become malformed so even if i'd somehow freed the cable inner, that outer still wouldn't properly sit in the control mechanism any more. so, if you try to move the cable inner from the valve end, you know what the likely outcome is at the other end.

no, you need to kludge it. the bulb has long wires and sits in a little plastic socket. the bulb's wires are folded over some plastic tabs that then get pressed against a piece of circuit board when the socket is inserted. you can remove the bulb, and bend the led leads into the socket in the same fashion. i suggest thinning them with sand paper a little too.

the best bit tho is figuring out orientation - has to be the right way around! you can get bi-directional led's but not 12v afaik.

or just swap the bulbs about. "1" or "2" are rarely used and should have plenty of hours left.

they're not metal lined like old throttle cable, they're a fully plastic outer. if they're stuck, it's because there's some adhesion happening, and that's not a simple lube issue. go ahead and try, but i don't think it'll work, and i doubt the longer term effects of the oil interacting with the plastic outer.

OK. I've got it though it doesn't look easy to replace that cable.

I've used these LED indicator lights on some hobby projects before and Radio Shack has a ton of them.

In Europe these kind of cables are called Bowden cables. It's a more descriptive name than just "cable."

once you have the controls out, it's actually very straight forward - the routing is simple and it just pushes through the bulkhead grommet.

yes, but make sure they're 12V - you don't have room to solder in the usual series current limiting resistor for a traditional led here.

well, yes and no. traditional bowden cable has a steel helical outer. this control cable does not - it's all plastic. i'd therefore prefer to call it control cable, not bowden, but you make a good point.

lube works with rust powder - not the case here. it appears that the cable outer is getting too hot, and physically bonding to the wire. or its "lubricant" liner is.

just the outer is plastic [polyethylene i'm guessing]. the inner is single core solid steel wire.

right - constant bending = fatigue.

didn't work for me.

Thanks for the info, I asumed the cables were helical metal outer and woven wire inner. Have never encountered an all plastic cable, or do I remember speedo cables being plastic, but then they usually broke rather than seized.

Try a Silicone/Teflon based lubricant spray ???

Al Moodie.

That would work if you removed the cables and hung them vertically and sprayed&soaked for a day or two, but if you have to take them out anyway....

IMO, GW