KEK

1925 Buick roadster wiring diagram

Recommended Posts

Hi everyone - I took my roadster out for its first test drive to check out the brakes and had an electrical problem that left me stranded along side the road. I found a loose wire and was able to fix it to get me back to my shop. Looking at the wiring I don’t think it’s correct. Does anyone have a wiring diagram that shows how the ignition switch and amp meter are wired? 
 

Thanks Ken

Share this post


Link to post
Share on other sites


Benefits of AACA Membership.

Posted (edited)

1923 thru 1926.   Lots of black background to eat all your toner on the 1925 version.  Hugh

 

845987605_1923WiringDiagram-FromLeif.thumb.jpg.579509aa930deb64d2bb8d9fbed9b8b1.jpg1024961765_1923-24ignition2.thumb.jpeg.dc1e67d22f247c1b05a4988c9085be07.jpeg

 

 

1477199956_1925Buickwiringdiagram.thumb.jpg.ad1703a8e625ef141e6fa76cb1c89d2e.jpg1580731123_1926BuickWiringdiagram.thumb.jpg.44084844ec6996732f8124df80684bcb.jpg

Edited by Hubert_25-25 (see edit history)
  • Like 1

Share this post


Link to post
Share on other sites

Thanks Hugh - this is just what I need to get me started. My shop manual has no diagrams at all. So from what I can see the starter pedal is hot all the time. That makes me feel a little more comfortable with the wiring since my engine will crank with the ignition in the off position. I see some wires that may be original and others have been replaced. My assessment is I need a new wiring harness. I also don’t see any fuses in the wiring diagram. I assume this was typical of the era but makes me very nervous not to have the system fused. Did you install a fuse in you electrical system?

Share this post


Link to post
Share on other sites

Hi KEK, I see the wiring diagram lists a circuit breaker at the ignition switch.  My understanding is that the early Buicks used circuit breakers instead of fuses.  You might check to see if your ignition switch has a breaker or if it may have been removed at some prior time.  Also it may have been bypassed ar some time in the past because it was not working correctly.

Share this post


Link to post
Share on other sites
Posted (edited)

Ken, 

    Yes, the engine will turn over anytime the starter pedal is depressed.  I would replace all the wiring.  I made an original harness for my car.  I made a few upgrades to the wiring where I felt it was lacking the proper gauge.  I could have also bought one from Rhode Island wire.  I added turn signals and brake lights as well.  Our harnesses are identical.  This is the spreadsheet that I used for making and cutting the wires and purchasing everything.  I did install a fuse block to the back of the ignition light switch.  Others have put fuses in other places.  I just use the one fuse and I keep a spare in the other spot.  The ignition switch has a thermal limiter, but i don't trust some of this old stuff, so a fuse is a good idea.  Also if you have a short, the limiter will just keep getting hot and then cooling off until something gives, so a fuse is a better idea.  My fuse is on the ammeter line to the ign/lighting switch, so only the ammeter is unfused.       Hugh

 

 1282192465_WiringSpreadsheet.thumb.JPG.7ec9c00bec46169a82a6bacb8caecc24.JPGIMG_7913.thumb.JPG.ace159c6609d428bb8e48edd8ec65dc4.JPG

Edited by Hubert_25-25 (see edit history)
  • Like 3

Share this post


Link to post
Share on other sites
13 hours ago, Hubert_25-25 said:

1923 thru 1926.   Lots of black background to eat all your toner on the 1925 version.  Hugh

 

1477199956_1925Buickwiringdiagram.thumb.jpg.ad1703a8e625ef141e6fa76cb1c89d2e.jpg

 

 

Try printing this one (same image, using the "negative affect", black becomes white and white becomes black):

 

1477199956_1925Buickwiringdiagram.thumb.jpg.ad1703a8e625ef141e6fa76cb1c89d2e2.jpg.cd222acf4069cf284ce1e5966c9d90ca.jpg

  • Like 1
  • Thanks 1

Share this post


Link to post
Share on other sites

Don,     That is a really neat trick.   Thank you.      Hugh

  • Like 1

Share this post


Link to post
Share on other sites

Hugh - I am still surprised by the detail information you provide! its amazing. Thank you for making this project easier. I will replace all the wiring as you suggested but probably not until this winter when I can dedicate more time to finish the job once I start. Don the photo printed out like a blue print - very cool. Thanks

Ken

  • Like 3

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now