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Problem with fan speed / heat

ANYTHING TO DO WITH CHANGING THE AIR TEMP INSIDE YOUR VAN.

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completetech
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Problem with fan speed / heat

Post by completetech » Tue Nov 06, 2012 4:09 pm

So I'll try to make a long story short. :rolleyes:

I have never really had any type of heat or AC blowing when set to the first setting on speed. but 2-4 always worked.

For some reason now that we are getting cold weather the controls only seem to work when they want to. I can turn it to full blast (i.e. 4 on the knob). and if it wants to work. it will. most times though it just doesn't work.

I guess I am looking for some basic troubleshooting tips on this issue.

As far as the heat. I notice that the temp gauge only seems to get to about half way between the cold mark and the next mark with number written on it (210 I think, sorry dont have the van in front of me today). I'm thinking that this may be either one or two things. Either..... 1.) the thermostat is bad, or 2.) I put in way to much coolant and not enough water when I first purchased the van and changed out the fluid.

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Re: Problem with fan speed / heat

Post by blacknome » Tue Nov 06, 2012 5:50 pm

The fan resistor block is pretty famous for burning out and causing the problems you mention 99.9% of the time. I just replaced the resistor block and the fan ( mine was a little noisy sometimes ) about 2 weeks ago. Cost about $50.00 for the parts from rock auto and took about hour to swap everything out. The new part is a little larger than the old so it comes with a template to enlarge the opening ( dremel is great for this ).
If that doesnt work then it might be the switch on the dash so you will break out the test light and see if you get power in and out from the switch at each setting.

Coolant or straight water should get to pretty much the same temp during operation so the "mix" is not the issue. Maybe a thermostat stuck open ??

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Re: Problem with fan speed / heat

Post by timelessbeing » Tue Nov 06, 2012 6:17 pm

x2 on the resistor block. Common problem here.
viewtopic.php?f=39&t=5345

I wouldn't rely on the temp gauge either. If you can get your hands on a OBD tool then read the temp from the PCM. On my van, I get different readings.If you had too much coolant then the engine would get too hot (maybe not in the winter). Ethylene glycol carries away heat poorly compared to H2O.

completetech
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Re: Problem with fan speed / heat

Post by completetech » Tue Nov 06, 2012 7:14 pm

is there a way to test that before hand?

and as far as testing the switch inside the vehicle. I just thought of this. I just got a new stereo put in and maybe somehow they messed something up. #-o

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Re: Problem with fan speed / heat

Post by timelessbeing » Tue Nov 06, 2012 7:37 pm

Of course you can do testing. A multimeter can be purchased starting at around $5.

Then follow this diagram.
viewtopic.php?p=85094#p85094

Start probing from the source, the fuses, and work your way out to the load, the motor. Make sure you are getting voltage where it should be. 12V in most places, and the resistors should drop it to something lower like 3, 6, and 9.

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Re: Problem with fan speed / heat

Post by completetech » Wed Nov 07, 2012 1:45 pm

wild stuff. I just got to the office and started the van to warm it up and get it down by the door so i could work on testing it. now the stupid thing is working.

not sure what to check at this point. should I start at the switch? or should I test the resistor???

completetech
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Re: Problem with fan speed / heat

Post by completetech » Wed Nov 07, 2012 2:57 pm

so the switch seems to be working. but I blew a fuse now. wild stuff. I tested on the orange wire as it says to the ground that is on the doghouse. But it blew the fuse. And of course all my fuses (not sure WTF they are there) are at home. So I guess its time to button up and drive home.

As far as the temp which does seem like its unrelated. But the max I could get was about mid 130's. Way below what I am suspecting that I need it to be. Time to throw in a new thermostat.

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Re: Problem with fan speed / heat

Post by timelessbeing » Wed Nov 07, 2012 6:46 pm

If your blower is working intermittently and it's blowing fuses, then it's either on its last legs, or you have an electrical short somewhere.

How do you know the tstat is stuck open? Is there coolant flowing to the radiator when the engine is cold?

What's with the spammy signature? It would be more helpful if you put some van info in there. :dunce:

completetech
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Re: Problem with fan speed / heat

Post by completetech » Wed Nov 07, 2012 9:36 pm

I was trying to say that I blew the fuse while trying to test for voltage off the orange wire.

As far as the thermostat. I am just making assumptions as its not getting hot.

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Re: Problem with fan speed / heat

Post by completetech » Thu Dec 27, 2012 7:52 pm

so thermostat was replaced and flushed and filled properly. now I have heat. But still a problem with the fan.

The fan did start to work again. However I have somewhat a new issue / same issue. The fan only seems to now work on speed 3 or 4 not one 1 (which it never seemed to) or 2. Wondering if the resistor is what I should replace as I can not seem to quite figure out the diagrams I have seen here.

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Re: Problem with fan speed / heat

Post by timelessbeing » Fri Dec 28, 2012 6:37 am

They cannot be replaced individually. Check the link I posted before.

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Re: Problem with fan speed / heat

Post by LiftedAWDAstro » Fri Dec 28, 2012 1:50 pm

For the time it takes, I would pull the resistor pack out and inspect it. I bet it's burned through in the 2 low speed positions. I have had to replace them before.
Current rides:
2013 Toyota Tundra DC 4x4
2008 Dodge Nitro 4x4
2005 Nissan Sentra 1.8S Special Edition

Mileage spreadsheet

Vans owned:
1986 Safari 2.5L 4 speed manual - scrapped
1995 Astro 2WD conversion 4.11 posi, shift kit, DHC rock rails - sold to Skippy
1998 Astro 4x4 D44, D60, NP231, full hydraulic system with 9k# Milemarker winch and snow plow - sold to Lockdoc
2003 Astro AWD all stock - traded for a 3/4 ton truck
2005 AWD, 4.10's - sold to skippy

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