Well for the second time this winter season, I have found that that heater blower motor has come on and drained my coach batteries.

This really upsets me as I don't want them sulfating which would require replacement.

The thermostat has an "on off" switch, and the blower is coming on regardless. I am guessing there is a faulty relay somewhere in the works.

Any thoughts, or am I on the right track?

Will be tearing into it soon, will keep all posted.

The thermostat switch on my 84 Regal is very hard. It will move easily toward the off posistion (left)and one would think that it is indeed off, but it takes hard thumb pressure to get it all the way home. There is a crisp "snap" sound when it is truly off. I learned this the hard way myself.

As a fool proof quick fix, pull the fuse until you find the problem.

I'm a newbie so others will be along with all the skinny, shortly I'm sure.

don

Depending on which t-stat you have, they are relatively inexpensive and if your coach is more than 10 years old (DUUH) it may be a good idea to switch (pun!) it out, regardless of the problem. However, I say 90+% probability it is the t-stat.

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"You are what you drive" - Clint Eastwood

I second dogill's remarks. You have to hear, and feel a clear snap in both directions with the on-off switch on the bottom of the 'stat. I believe the thermostat on its lowest setting will still turn the blower on when it's cold enough, if the on-off switch isn't really off.

This is indeed good news. I thought my T-stat was going haywire because it took so much pressure to get it to click off. Kind of like the slides on the GM airconditioning. I am always thinking I am going to rip the thing off of the dash. It was the same in an Olds Ciera I had once.

Dave, a stiff dash board heater/air conditioning control is usually due to binding in the cable. Generally the cables are just piano wire in a spring-wound housing, and work with a push-pull action,. They get dirty and rusty when they get old, which increases the friction. If they have to make a lot of bends, or a very sharp bend, they're harder yet to work. Fancy ones will have a plastic cover. Think of the brake cables on your 10-speed bike - same principal.

Sometimes the mechanism they operate will get stiff too. I haven't had much success lubricating the cables, I've done better just buying new.

Bill h might also have some ideas about these control cables, and I'll bet he knows the proper terminology for them too.

[This message has been edited by olroy (edited April 02, 2005).]

I guess I should have added that I dissassembled the thermostat, and very clearly can see that the contacts that operate the blower are open. I am going to disconnect it next, and trace the wires.

I bought a replacement thermostat and will install it regardless. There is now a smallish dent in my old one...I will leave you guessing as to why

quote:

Originally posted by olroy:

Bill h might also have some ideas about these control cables, and I'll bet he knows the proper terminology for them too.

OK, Roy,I'll take the bait. It is called Bowden Cable, but the term is rarely used any more. When I am constructing some mosbegotten Rube Goldberg thing or other, I use Bowden cable with a nylon liner to avoid the usual difficulties.

To free up a recalcitrant existing all metal cable, I shoot it externally with liquid wrench or PB Blaster as I flex the housing to allow penetration. Having the wife move the lever at the same time helps, too. The mentioned products are not the best as lubes, though, so I usually follow up a week later with Dri Slide, as it leaves a lasting residue of molybdenum disulfide. If you are lucky enough to have an inner cable with a straight end, just pull it out and squirt some dri slide in the housing.

Some Bowden cables have a plastic jacket over the coiled metal outer housing. Then a motorcycle cable lubricator is best, again using Dri Slide. It is a little metal clamp with a rubber sleeve that squeezes down to seal off the end so the lube is forced down through the housing and out the other end. An unjacketed Bowden cable will drool, so use rags to catch it.

If you don't have a cable lubricator, you can use an old mc trick if you can remove the bowden cable from the vehicle.
Make up a sort of plastic funnel using some heavy plastic wrap or a ziplock bag by tightly wrwapping the plastic on the outer cable sheath using an elastic band or wire tie. It should be fastened tightly just below one end of the cable but on the outer sheath while leaving the inner wire/nipple connector exposed. You then hang the whole setup vertically from whatever. A tall enough step ladder works well, with the cable suspended from the cross brace or paint shelf, plastic wrapped end up. Climb up the ladder and fashion a funnel shaped opening with the plastic. Pour or spray in the lube and let her hang until tomorrow. Don't forget to put a pan or something under the bottom end of the cable to catch the lube that runs out the other end.
If you want new cables, and you have an old time mc repair shop (not likely the big HD dealer)around, take in the old cable and he'll remove the end pieces/nipples or whatever's Barth specific and us 'em to solder you up a new teflon coated bowden that won't need to be lubed.
Don

quote:

Originally posted by bill h:

OK, Roy,I'll take the bait. It is called Bowden Cable, but the term is rarely used any more. When I am constructing some mosbegotten Rube Goldberg thing or other, I use Bowden cable with a nylon liner to avoid the usual difficulties.

To free up a recalcitrant existing all metal cable, I shoot it externally with liquid wrench or PB Blaster as I flex the housing to allow penetration. Having the wife move the lever at the same time helps, too. The mentioned products are not the best as lubes, though, so I usually follow up a week later with Dri Slide, as it leaves a lasting residue of molybdenum disulfide. If you are lucky enough to have an inner cable with a straight end, just pull it out and squirt some dri slide in the housing.

Some Bowden cables have a plastic jacket over the coiled metal outer housing. Then a motorcycle cable lubricator is best, again using Dri Slide. It is a little metal clamp with a rubber sleeve that squeezes down to seal off the end so the lube is forced down through the housing and out the other end. An unjacketed Bowden cable will drool, so use rags to catch it.

If only the fan is comming on and the burner is not, the problem is the temp switch inside the heat chamber that operates the fan.