Defective heater control (only some speeds work); how to fix

[t00manyusers]

Hi all,

I have a 2008 base Versa, no AC. Just recently, the first three speeds on the heating/ventilation fan stopped working: 1,2,3 do nothing, and 4 turns on to maximum speed. How can I troubleshoot this? I took apart the dash, but do not see anything obviously wrong. Is there a fuse or an electric path I should be tracing?

Thanks!

[Rogue One]

It could be the dash control unit. I believe it's part # 27510-ZW80D. Part costs between $155-$165.

[t00manyusers]

It could be the dash control unit. I believe it's part # 27510-ZW80D. Part costs between $155-$165.

Eek! you think so? Reading the service manual, they say that each speed position runs along a different electic line, and if SOME are not working, to test those lines - it would seem to me that if the dash control unit failed, then none of the speeds would work, rather than just one?

That said, i've no idea what I'm supposed to trace. Haven't tried to figure it out yet, so was hoping someone out there knew.

[Rogue One]

Hmm, didn't know that. I'm wondering if there could be a problem with the contact points on the knob control, say worn or corroded. As the knob is not frequently turned all the way up, the higher setting would have less wear and tear.

[t00manyusers]

Hmm, didn't know that. I'm wondering if there could be a problem with the contact points on the knob control, say worn or corroded. As the knob is not frequently turned all the way up, the higher setting would have less wear and tear.

Yep - that was my first thought, too (hence why I took the dash apart). But I saw nothing untoward - and then I started thinking that it's not like they gradually failed: the positions worked fine, car was parked for a few weeks, and bam - no more positions 1-3. Not even occasionally. Very weird. Hmm.