Yaw Damper Light Illuminated

[kctanker]

I've got a snag on the B737-300 . The autopilot yaw damper light illuminated whenever it is airborne, the snag will disappear when the a/c is on the grd.
I reckond that it could be the wire linked from the o/p of AFC module thru the D499 plug to the yaw damper light assy .
Can anyone help me to locate the wire routing to help me in my troubleshooting,
Thanks alot

[Pete]

To find the wire digrams you are asking for,first you must find the production number, for your air craft.Then go to the hook up list and put in your plug number D499.From there you can find the different wiring diagrams.In the digrams you can find the station numbers and where your wire is routed and which boundel number your wire is in.Good tip is to read the front matter how the wdm is used.Good luck

[sander]

Ok, firstly u need the drawing to find your wire, when u know the suspect wire u find the wire loom number that u are looking for.
U allready know plugnumbers so u most likely allready know wich loom is suspect.
Then u go to the WDM and find chapter 91 (charts), then look up MISCELLANEOUS and find the wire loom number that u are looking for.

Now u should have a drawing of a airplane with the routing shown on it. easy peasy. Good luck actually finding the fault though
(try to have a avionics guy do it).

[airtech_59]

Hello!From my experience:YAW DAMPER light comes on often and you can't switch on YAW DAMPER.Then you go in EE bay to YAW DAMPER COUPLER and you do BITE test and you do latched fault reset.As a rule,it helps 90%,if no any other defects in YAW DAMPER SYSTEM...