1991 Honda accord Heater/ac switch problem
 

I guys it Pito once again....Thanks to Poorman212 and Crispin i solved the previous problem of no dash lights and tail lights... look at my old post for knowledge.

i have a switch that does not work. it doesnt function in all positions....i used the test light i dont have any constant power..on or off from the switch itself...

I figured that the large blue wire w/ red stripe is the power source and the large black wire is the neg..all the other smaller wire is to control the speed of the motor.

i do have light power to the buttons that position the vent to direct the air flow... i do hear that working. no motor blowing.

Since i had the dash already dismantled from the previous problem...i ran the wires down the left side of the dash board then it made u turn and came back down the the center and underneath the carpet...then made a right turn and underneath the two computer consoles...the large black wire gets grounded at the passenger side kick panel with two other black wires. the large blue with red stripe wire continues up that same side....thats where i am at right now.

the blower fuse is not blown.

Did I post this right?

Yes you posted it right.

I am going to wait for Poorman or someone else who understands how the A/C controls are wired to chime in.

I do know that there are 1 or 2 relays involved with the blower system.

My guess is going to be something to do with a relay.

Question, did the controls used to work? If so what happened?

Pito, also have you downloaded the Service manual yet?

Looking at the wiring diagram (page 948 in service manual) there are 2 relays involved that must be working.

1 is in the underhood fuse box and the 2nd is under the dash somewhere.

You should not have any power at the switch, like much of what honda does things are controlled by grounding circuits

How it works is going to the motor is a yellow/black wire - that is the power source.

The blue/red is the other wire that goes to the blower motor (from the blower resistor) and it carries the ground.

Here is what you should do.

Probe the yellow/black wire on the blower motor with the key in the 'on' position and see if you have power there. I guess you do not. At that point I would pull the under hood relay and tap it some and re-install. If it still does not work I would replace the relay.

I downloaded the service manual...I will read up on that tonight and tomorrow.

Did you try this test yet?

Probe the yellow/black wire on the blower motor with the key in the 'on' position and see if you have power there. I guess you do not.

At that point I would pull the under hood relay and tap it some and re-install.

If it still does not work I would replace the relay.

Yes wire diagrams are fun reading :)

As crispin said, check for power at the motor.

If there is not power there, I personally would start with the underdash relay. Test the relay, test the inputs to the relay.

Sorry guys..I had to work a lot this week...wife went to work as well...she can drive now at night...I still have the entire dash disassembled. My wife nags me when are you to finish the car...this is where I'm at.....besides the aforementioned ..I changed the blower relay....its not the relay...I returned it and got my money back...I had the old relay tested...its still good.

Pito - we said to test for power at the blower motor before you start replacing parts.

Have you tested for power at the blower motor yet?