Alright, so I went to flip my heat on the other day, and as soon as I slid the lever to turn the fan on, the blower came on, but started flipping on and off and I could hear what sounded like a relay on the passenger side area clicking on and off....what is likely the cause of this? Where should I check first?

 

You have a short in the logicon, likely in the fan speed control. You should try moving the speed lever around a little. If you can find a position that the fan doesn't click on and off, that is the problem. You can try cleaning with some spray-in contact cleaner,. If that doesn't work, you need another working logicon.

BTW, that rapid cycling will also switch the compressor on and off at the same rate. eventually you will burn up the compressor clutch. It happened to me!

 

yea...i only turned it on for about 5 seconds...and actually, if I recall correctly (I'll check tomorrow) I don't think the fan came on at all until the slider was almost all the way to high...then it kicked on a cycled a few times and I shut it off. Haven't turned it on since (got back up into the 60's ...beautiful windows down weather!)

I'll see if my buddy has a spair logicon we can throw in to test it. I'll try to remember to post back when/if the problem is resolved.

 

Try cleaning the slider with contact cleaner before you replace the logicon. Get it at radio shack. Replacing the logicon is very straightforward, but it is a pain in the ***.

Good luck!

 

Alright...just went fooled around with it (this is with just the key on and the engine off, if that makes a difference). It seems to click on and off towards the lower end of the fan speed...if I push it all the way to high, it didn't cycle on and off. It seemed to be the worst in the first 1/3 of the slider bar. It had hardly any control in that range...just cycled on and ff...after about halfway, it seemed to stabilize a little, and on high it didn't cycle any. Still thinking it's the logicon?

I read on the removal of it...sounds kinda lame. I think I'm gonna try removing the top trim on the dash to get to the plug...I may try reaching up through the dash first...but I'm doubting this will work as I don't have the smallest hands in the world.

 

Yes its prob your logicon (funny this is third time I have replied to a logicon prob and now there are a few more posts that are prob the same logicon issue, winter is here)

it really is simple to remove and replace once you understand. check FSM for removal procedure (remove vents remove shfter surround remove ashtray remove four screws holding surround unhook lighter and light etc etc. not hard really if you pay attention careful cracking is easy on all this stuff if you rip at it)but a tip if you are replacing with another is it will seem loike you need to cut the wires on back left or search for the connector somewhere up under dash but this is not the way, there is a screw at the back of logicon and then you remove the white plastic cover and unplug the wires from the circuit board inside...this might not make full sense right now but as you take it apart it will.
I grabbed a few logicons from wreckers and other parts cars I have had as have found MANY logicons have failed (had 6 rex's now).

hope this helps a bit

thought I would add that I have mixed and mathced different boards front sliders etc from several diff logicons to get one that works, sometimmes its a circuit board sometimes a slider or cold solder etc.etc. never yet have I found it to be any other part in the heater system besides logicon (ok once on a friends his blower motor was fried but much rarer)

 

mine does the same thing. I have 2 extras... but Im too lazy to swap them out. usually a nice "love tap" with my fist helps it out

a flat head screw driver and one of those Z shaped screw drivers works to remove the defroster trim. Its made of metal so it wont bust apart. The plastic vents however are very brittle so dont bend them.

There are 3-4 metal pop clips you can pry open with a screw driver. Then jam something like a hammer head under it around the idiot cluster to give you space to stick the angle "Z" screw driver. The plugs right under there.