11 replies to this topic

[(_8*(l)Homer]

Hi,
So, last night driving home from Boston, I noticed there was no fan blowing the heat into the car. Here is what I found:
If the ECC is set to Full hot or cold, fan blows correctly on either auto or any fan speed setting and any position setting.
The ECC DOES NOT blow if the temp is set to anything else, no matter which fan speed or position is set, with one exception.
The one exception is that it bows properly if set to defrost (turns ac on)

Any suggestions?

[BEJinFBK]

My first thought is the cabin temp sensor.
A quick shot of canned air usually clears that.
Are the ECC lights blinking on start up?

[(_8*(l)Homer]

Yep, I blew it out with canned air (the one with the console switches) and there are no blink codes from the ECC. There are more temp sensors, where are they? I think it's one or more of those.

[BEJinFBK]

Usually, if there's a bad sensor input, you'll get
the ECC blinkies for 20 seconds at start up.
But AFAIK, you need something Volvo specific
for actual diagnostic trouble codes.

As for the additional temp sensor, it's a little buried.
There's another one in the duct near the blower.
It's just below the power stage, next to the motor.
Look for "7/11" in this component locations PDF:

 98 x70 ECC Component locations- both.pdf   370.25K   14 downloads

FWIW, here are the diagram pages, too:

 98 x70 ECC Diagrams- both.pdf   522.29K   10 downloads

[(_8*(l)Homer]

Cool, thanks, I will pull these this weekend (after I replace wheel bearing) and see what I can find. Luckily there is an electronics shop near by where I could pick up a thermocouple if needed.

[(_8*(l)Homer]

This is very strange. I have noticed that the blower works properly if my vehicle speed is under 20mph, between 20 and 30mpn the blower will vary in speed.
Scenario:
Blower settings set to full fan, 72deg
speed = 20mph blower blows at full
speed = 25mph blower blows at half speed
speed = 30mph blower is off

I can speed up and slowdown the car to inversly slowdown / speed up the blower.

Anyone seen anything like this? There are no error codes. I have VIDA would the dice tool allow me to view the output from the blower system?

[BEJinFBK]

Starting to sound like you may have charging system problem.
I'd start looking at your voltage while driving.
You could start easy by just hooking your meter up to the
cig lighter and keeping an eye on your levels real time.

[(_8*(l)Homer]

Will do. So, if I see that there is less than 12v min does that mean I need a new alternator?

[BEJinFBK]

Maybe - But checking all the components is the starting point.
A volt drop test to check out battery, alternator, cables, connections
and all that stuff as a system is probably what you want to look at.
The battery and alternator can be individually tested in the car.

[(_8*(l)Homer]

K, so hooked up a multimeter yesterday and drove for over an hour with it Voltage is relativly stable. 13.3v at idle and 13.6 while driving, so I don't think that is the problem.

Any other suggestions?

[(_8*(l)Homer]

So, I swapped the ECC out with the one from my junk S70, works like a charm.

[BEJinFBK]

Glad you found it. Had me scratching my head...
I guess these cars really are getting old.