smoke from under dash

I have a 1986 ford F150 4x4. last year as I was driving to work I smelt buning leaves and then the cab filled with smoke in about 15 seconds. I pulled over and shut off the truck. It cleared up, and I finished my trip to work. My radio had been shorting out so I removed it and felt I had solved the problem though I didn't see any burnt wires. Yesterday, about a year later it happend again! Pulled the glove box as the smoke comes from that side and could not see any thing like burnt wires. The smell is deffininetly of burnt leaves not wiring insulation as I would expect. It is not coming from the heater or the engine comparment, as the defrost was on at the time and the smoke did not come out the defrost but from under the glove box. Have looked under both sides of dash and found no evidence of burnt wires. Any ideas

It sounds like you have a mouse nest inside the heater box. Does it happen only when the blower is on? My truck did the same thing and I found a nest that was built around the blower resistor inside the heater box. The resistor is just a coil of wire which gets hot enough to make the leaves smolder. If I remember right, it is located in the heater box above the transmission hump. There is a two or three wire plug on it and two screws that hold it to the heater box. Remove it and look inside for burnt leaves and other things from a nest. There was so much stuff inside mine that I ended up taking out the heater box to clean it all out. I don't know why the smoke wouldn't be coming out of the defroster though but if it smells like burning leaves it probably is!

This was exactly right. I found a pile of leaves near this coil that were burned. Cleaned out the rest of them and wondered why Ford used this design? I have talked to another neighbor who had the same problem with his Ford. Seems like a fire hazard that Ford would have known about. When I talked to the dealer they said they had never had any problems like this. Thank you kindly for your help. It is greatly appreciated as we can drive the truck with confidence again. I guess we will have to clean out the leaves once in awhile. Thanks again.

The guy I bought my truck from only used it one week a year during hunting season so the mice had plenty of time to make a nice home in it. A week after I bought it I turned on the blower and within five minutes my cab was filled with smoke. I shut it off and disconnected the battery before I started looking all around the cab to see where it was coming from. As you I couldn't find anything so I reconnected the battery and drove it a quarter of a mile to the fire station and told them what happened and that if it was going to burn I wanted them handy! Of course I had shut the blower off by this time and no smoke came out. One of the firemen came out and looked around and saw nothing but said it did smell like leaves burning! I drove it home and looked some more and then remembered the blower resistor so turned on the blower again and shortly after more smoke so I knew what was causing it. The heater box was packed with leaves, twigs, insulation and whatever else they could find. Your thread made me smile when I remembered seeing smoke pour out of my truck, the smell of burning leaves and the panic I felt trying to get the battery disconnected! Sorry, but it's nice to know I'm not the only one this has happened to and glad your truck didn't burn.