Hey all,

Just picked up a 2002 Doblo passenger van. The heat blower is not functioning. Traced it to F8 fuse. Replaced it and it blew it again. Replaced it and was able to run the fan for a bit on 1-3 settings. Set to 4 and it blew the fuse.

Thoughts? Advice? Hoping it's just the relay and not the motor...

Hi

Its controlled by a resistor..

Less power on speeds 1,2 and 3

So either a bad fan.. or burnt wiring around the resistor

See this for basic info:
https://www.fiatforum.com/grande-punto/314051-heater-faq.html

I have been reading up on the resistor. Is it accurate to say that the fan would not work on settings 1-3 if the resistor is fried but still work on 4?

Or is it likely it fried so bad that there is a physical short in there now?

Thanks!

Burnt wiring at its plug #1 issue

There is also a relay (R8) under the hood that is powered directly by fuse F8 but I’m not entire sure of its function in this system.

My bet is on resistor

Dobro said:

I have been reading up on the resistor. Is it accurate to say that the fan would not work on settings 1-3 if the resistor is fried but still work on 4?

Or is it likely it fried so bad that there is a physical short in there now?

Thanks!

Click to expand...

speed 4 runs the fan on full speed bypassing the resistor
Probably drawing too much current at full Speed could be a bad connection or the fan itself

The resistor connector looks perfectly normal. So I guess I need to figure out a way to test the fan itself and possibly the switch.

The only other thing I’ve gleaned at this point is that the fan doesn’t come on on 1 or 2, comes on on 3, and blows the 30A fuse on 4. Odd....

Dobro said:

The resistor connector looks perfectly normal. So I guess I need to figure out a way to test the fan itself and possibly the switch.

The only other thing I’ve gleaned at this point is that the fan doesn’t come on on 1 or 2, comes on on 3, and blows the 30A fuse on 4. Odd....

Click to expand...

Put a meter on the resistor area.. its possible your speed dial switch is the issue
( when you posted earlier..it read as if 1,2+3 all worked.. has this changed?)

Yes. I misspoke earlier. I put another fuse in and re-tested it. No fan on settings 1 & 2. Comes on on 3 and blows the fuse at 4. Not working in all settings 1-3.

Can you give me any advice on testing the switch? That would be awesome to rule that out. Or know that it is the problem.

You need a 12volt test meter

I have one. What am I testing? Resistance? Continuity to ground? I have a lot of experience with a multi-meter but not with this style heater control.