1994 850 re: obd codes 414 & 418(New Member)

[volvodude850]

I just joined this today,I posted and have enjoyed "0 new messages" for my efforts; so I'm thinking I need to "clue in". I just read some posts regarding the courtesy of syntax, grammar and punctuation and it "dawned" on me that, perhaps, I was a little careless and hasty in my post and assumptions. Please allow me to edit this previous post in an effort to conform to the culture of this forum, and illustrate the proper respect that you professionals deserve.

Hello, my name is John and I am a new member. I own a 1994 850 that I attempt to work on myself, whenever possible. I am self-taught and have a few craftsman tools that empower me to believe that I just may get lucky and fix something once-in-awhile. This is my latest problem:
Yesterday when I turned on the heater nothing happened except flashing lights (20sec. long) on the recirc/ac dash-panel. I Pulled the obd codes and got 414/418.I removed the drivers side grab bar and I accessed the temp sensor inlet fan (drivers side), blew it out and lubed it. I inserted a dental pick through the hole and the fan seemed to spin no problem. I turned ignition and still the blower fan wont come on and I continue to get the recirc/ac flashing lights for 20 seconds. I went back to the obd and I am still getting same codes. I've been told to just replace the resistor and ignore the inlet fan problem and to the contrary I've been told to make certain I rectify the inlet fan problem first and then if no blower motor, replace resistor. I was pondering (because I don't really know what I'm doing) if it's possible to safely jump (bypass) that inlet fan altogether. Any feedback would be greatly appreciated and I thank you in advance.
John

[Ozark Lee]

Welcome to MVS. I am going to assume that you pulled the codes from port B-1 which is the proper port for the climate unit.

The 4-1-4 code won't keep the blower from operating but the 4-1-8 code will. Chances are it is a bad "power stage" which is a fancy name for the electronic climate unit's blower resistor. It really isn't a resistor at all but that is how many of the parts catalogs name it. You can't really test it beyond replacing it with a known good unit but what you can test is the blower itself. Unplug the large connector on the power stage that has the blue and black wires. Use a jumper wire to short the two wires together and the blower should run at full speed and it shouldn't make any bad bearing noises. If it is noisy (beyond just normal air noise), then, at a minimum, you need to lubricate the bearings on the blower and get it to operate without bearing noise before you replace the power stage. A bad blower will kill the new power stage quickly and the power stage is a pricey item.

After the power stage is replaced clear the codes and see if the 4-1-4 code even comes back.

...Lee

[volvodude850]

Thank you Lee! I will do what you suggest.
John