Bypass condensers

Capt Lee P · Post by **Capt Lee P** » Mon Sep 10, 2007 6:49 pm

Help!

What are "bypass condensers" as used in the main wiring harness at the junction boxes on the firewall? My truck is an ex-French 1944 353 rewire job and not as per TM 9-801.

Do they need to be replaced? I am having trouble with my brake lights (could this be a source or a part of the problem)? Who sells bypass condensers?

Thanks,

Lee

John V Cliche · Post by **John V Cliche** » Mon Sep 10, 2007 9:25 pm

Hi Capt,
Give Joe Hall a call at Vintage Wireing of Maine, he is the " go to guy " for this question.
He advertizes in MVM and Supply Line.

Hope this helps
John

Capt Lee P · Post by **Capt Lee P** » Tue Sep 11, 2007 3:36 pm

Bypass Condensers: what are they, what do they do, and where can one buy them?

I called Joe on the recommendation of Bob at Vehicles of Victory as Bob was not sure what function they did. Joe at Vintage Wiring also was puzzled as to their function and drew a blank.

dr deuce · Post by **dr deuce** » Tue Sep 11, 2007 5:34 pm

They are bypass condensers are for electrical supression.

You can check them with an ohm meter. They should read about 0 (zero ohms) thru and infinite ohms to the case. If not, there is something wrong inside.

Capt Lee P · Post by **Capt Lee P** » Tue Sep 11, 2007 5:50 pm

Dr. Duece

Thanks, but . . .

If they are not any good, do you just disconnect them? Do they make a difference? Should I look for replacements? Do you think they would have any effect on my brake lights working properly?

Thanks, Lee

dr deuce · Post by **dr deuce** » Tue Sep 11, 2007 6:13 pm

They have no affect on the operation if you remove them and wire them straight thru. Try that for a test.

One issue with brake lights is that it takes little pressure to activate the switch if you have the correct switch and it is working correctly. If you have just a replacement switch, you will have to stand on the brakes to get enough pressure to get brake lights with a good working hydrovac and moving truck. I know it is blasphmy, but I use a lever action brake light switch in all my ww2 GM products. It follows the brake pedal and the minute you touch the brake, the lights come on. The switch is from a 57 chev PU truck. It mounts to the bottom of the toeboard.

Capt Lee P · Post by **Capt Lee P** » Wed Sep 12, 2007 12:08 pm

Dr. Duece

Thanks for your thoughts. I am going to mount as you suggested a brake arm switch from a 57 Chevy pickup. Any special location for mounting?

Thanks again, Lee

dr deuce · Post by **dr deuce** » Wed Sep 12, 2007 4:54 pm

Once you see the switch you will understand. As I recall, the mounting is between the pedals. You want to mount it up higher so that the minute the pedal arm moves away from the stop, the switch will activate. There are actually two different switches that I have used. One has the mounting flange bent one way and the other has the flange ment the other way. It just means about 1/2" difference in where the mounting holes are.

You need to make sure that the wires are routed so that they do not get burned by the ex pipe or pulled on by either pedal.

I will try to post a picture

If you are running 12v with an ignition resistor and the original 6v or = coil, I also use one of these switches on the other side of the engine to bypass the ignition resistor when starting like they did in the 60's. It does the same thing only this time it follows the starter linkage. Starts like summer time at 20 below!