1998 Honda Civic EX coupe. A/T. 170K miles

Vent selection no longer working properly and will only blow from top vents regardless of which button/mode is selected. Metal rod to blend door is connected properly and no movement or sound of control motor when key is in position 2 and each vent modes are selected on dash. Looking for info on how to test. Part is labeled as mode control motor in attached image.

 

Do you have access to the factory service manual or did you pull that image from the internet? The reason I ask is because the test procedure is stated under the part description.

So, I did a quick search for you as I watch the Formula 1 race. Use the search feature next time or do what I did and use Google; the procedure has been discussed before here on HT.

https://honda-tech.com/forums/honda-...ersed-2615060/

 

Yes I have the manual and I did see the test description reference on the diagram. Just wanted to avoid the possible extensive search through the manual to find it if someone has a quick link. I found a test proceedure for 7th gens which is probably the smae as for 6th gens:

1. Disconnect the 7P connector from the mode control motor.
2. Connect battery power to the No. 1 terminal and ground the No. 2 terminal; the mode control motor should run smoothly and stop at Vent. If it does not, reverse the connections; the mode control motor should run smoothly and stop at Defrost. When the mode control motor stops running, disconnect battery power immediately.

MODE CONTROL MOTOR

1. Use a digital multimeter with an output of 1 mA or less at the 20 k ohm; range. With the mode control motor running as in step 2, check for continuity between the No. 3, 4, 5, 6 terminals and the No. 7 terminal individually. There should be continuity for a moment at each terminal.
2. If the mode control motor does not run in step 2 remove it, then check the mode control linkage and doors for smooth movement.

• If the linkage and doors move smoothly, replace the mode control motor.
• If the linkage or doors stick or bind, repair them as needed.

 

And just to add, be careful when testing the motor. There is not a lot of room in there to do the test. I had a pigtail from a junkyard Civic to test mine.

 

Found a related post... good ole' Ron J. on HT and his many diagrams: https://honda-tech.com/forums/honda-...civic-2816037/ I made some long jumper wires with alligator clips a few months ago when I tested the condensor fan and a/c compressor clutch coil relay so, those will come in handy. Thanks for the replies and I'll update after testing.

 

Good to know! Curious question. Did your mode control motor quit out of the blue? Mine died after fiddling with the butchered radio harness I inherited from the previous owner(s) handy work.

 

Yes, as far as I can remember..it happened several months ago however been busy with other stuff getting in the way:

condensor fan replacement
clutch coil replacement
blower motor replacement
and other stuff.

 

Control motor failed test. Replaced with salvage yard OEM part ($13).. working well now.
Thanks for replies.