Re: TrevorK's 1955 Packard Patrician

Posted by HH56 On 2018/11/6 11:44:32

Switches can fail so they do not switch and could just keep the TL terminal active. If it is the 3 terminal switch check the plug on the switch and make sure the brake light wire (dark green) is connected. Sometimes those terminals loosen and can slide out of the plastic making poor contact with the switch posts. If contact appears good use a meter and see if the 12 volts to ground on the light green wire goes away and it switches so 12v is on the dark green wire when the brakes are active. If the brake switch is good the problem is farther along either with the turn signal switch or maybe a broken or disconnected wire in the loom.

If voltage is not present on the dark green wire it is the switch. Just my two cents but if you have an expensive original NOS type or even the VW replacement of the 3 terminal brake switch some just don't seem to have long life histories. While the 2 terminal switches can have problems too, they are inexpensive and readily available. If it were my car and you still have a 3 terminal I would consider converting to the modern replacement which uses an inexpensive 2 terminal switch and a relay to provide the switching function for the TL If you already have the 2 terminal switch and relay again check for switch output and then check that the relay is working by measuring for voltage switching at the relay. Some kits keep the original wire colors but others spliced in different colors. At the final loom connection the dark green is still the one to look for.

The drop in hydraulic kits are available from some vendors as well as the Pacific Northwest Packard region but you can also make your own for just a few dollars and some time. You could even go a step farther as many of us have done and eliminate the hydraulic switch entirely and go with all mechanical.