After fan speed 1 and 2 stopped working I brought new fan resistor and put it in. Upon making sure it’s working which it all does I noticed the resistor getting red hot and started smoking a little also. 

 

I quickly shut it off and thought maybe it was the fan motor itself being so old I replaced it with a new one. I plugged it in again and the same thing happens it gets red hot can’t touch it and smoking little. 

 

Scared to put it it back I case catches fire or something anyone had this problem? 

 

 

I would expect SOME heat from a resistor as it is restricting the flow of electricity, to the unit. However, to get so hot sounds a bit dangerous. I would expect a little fire retardant insulation surrounding the item and that it is not touching anything that can combust easily but still, it sounds dangerous!

 

Smoking itself, is suggesting it is too hot so I am going to ask you, is the resistor a cheap copy from a well known auction site? If it is, thats most likely the answer. 

 

If it is a genuine Skoda part, take it back and express your concerns! You could of course, do this over the phone but they will most certainly advise removing it and taking it back anyway.

 

Have you still got the old, malfunctioning one? If so, try replacing that to see if it overheats but not for too long, though, just to be safe. This may help you decide the new one IS getting too hot, if your old one stays cool but remember, the lower speed settings are where most resistance is done so they are the ones that I would expect more heat or noise to come from the unit!

 

I think you may have spent money on the fan unnecessarily though, which is a shame. Another thing to think of is, has any relevant fuse been replaced? You may have had a fault and blown fuses and inadvertently fitted too high an rampage one. This will then not blow, creating a bigger issue then merely blowing!

 

I think I am correct in saying the resistor can only plug in one way around but you may know that better then me as you have removed/ refitted it so unless it can be fitted back to front, this shouldn't be an issue. 

Also, I think they are fairly common parts among these models so buying and fitting the correct spec is  probably NOT the issue.

 

My guess is the unit was defective and you simply need to replace the replacement.

 

Hope you get to the bottom of this issue quickly and safely and welcome to all Briskodian! it is an invaluable website.

Check the cabin filter. The resistor needs a good flow of air in the heater casing to cool it. If the filter is blocked the resistor will burn out.

Yep, as Lee says, low air-flow rate due to a blocked filter will increase temperature of resistor. Zero airflow - if you are checking the resistor when it's out of the housing, will make it even hotter.

 

Also may be worth checking alternator output voltage (measure across battery terminals with engine running). Higher than designed voltage will increase power dissipation rapidly as it will go up with V²

Yes it is a £7 from eBay might be the problem. Will fork out for a more expensive one see what happens. 

 

I replaced the cabin filter about 8k miles ago I almost just put a new one in when I was doing all the work today as I was there. 

 

Yes i I am checking it when it’s out of the box just concerned with the heat it is producing got me worried and last think I wanted was a fire in worse case sinario.

 

Just wondering if there was anything else that that I could do or check. I’ll check the fuses quickly also as I haven’t done that either and see what’s what with them. 

I was thinking of asking if the resistor was actually in the airflow of the fan... I do seem to remember someone saying about removing the insulation to get at it though so I thought it was partially wrapped, so to speak. The insulation may well have been in front of the resistor though, rather than actually around it... Making it sound quieter and preventing the heat from touching the dash area and/or warming the cabin, somewhat.

The resistor goes inside the heater casing, so there is no insulation near it.