My question is in regards to the turn signal operation of my 68 XR-7. Everything seems to function normally when the headlights are off, but after turning on the headlights, the turn signal indicators on the dash stay lighted but do not flash when applying the turn signal switch. However, all of the external lights still flash normally when this occurs. I did have the original alternator rebuilt recently (also upping it’s output to 70 amps). The charging system is functioning normally and this turn signal issue existed both before and after the alternator rebuild.
Hmmmmm. Coach Jack, Bill, or Royce, where are you?
I wish I could help on this one, but it’s of my wheel house.
The front turn signal bulbs are dual filament bulbs, one filament is used for the turn signal and the other filament is used as parking lamps when the headlights are on. The turn signal filament ground is provided by the turn signal indicator relay K7 where as the parking lamp filament’s ground is provided by circuit 26 which grounds on the alternator case.
Since your dashlights are lit when the headlights are on, I suspect that the parking lamp power is backfeeding power through the turn signal filament and is then finding a ground back through to the turn signal indicator. Check the parking lamp housing for any burned or frayed wires and make sure that the ground at the alternator is clean and tight.
Coach Jack
MY car has done this as long as I have owned it (1975). Even just at idle with the brakes applied the dash blinker stops blinking, but the exterior lights are blinking. I always assumed it was just inherent to our cars.
I may not have made myself clear, the dash lights are not on when the headlights are on, but only when the turn signal is applied. They just don’t flash with the exterior lights when the the turn signal is applied’ as G68 stated.
The front lights are powered from the sequencer in the trunk. The dash lights are powered directly from the turn signal switch, with the flashing provided by the K7 turn signal indicator relay making and breaking a ground connection.
Your problem is backfeeding power thru the filament of the front lights thru the turn signal filament and onto the K7 relay for ground.
Even just at idle with the brakes applied the dash blinker stops blinking, but the exterior lights are blinking.
At idle, your alternator is not putting out enough power thus the current draw thru the turn signal lights is not sufficient enough for the K7 to break the ground to cause the dash indicator lights to flash.
Coach Jack
Is there a solution? Like I said, the original alternator has just been rebuilt with output increased to 70 amps, but I don’t know what the output would be at idle. Like G68, I may just have to live with it. At least I know that all exterior lights are working properly so traffic around me knows what I am doing.
I had the same issue until this was made available:
http://www2.cougarpartscatalog.com/store/p/15520-Relay-Turn-Signal-Solid-State-K-5-/-13A366-Repro-1968-Mercury-Cougar.html?attribs=76
Thanks Mike, it’s temporarily out of stock but i will be ordering one as soon as they become available. Could you tell me exactly where under the dash that it is located?
The old relay is mounted directly to the fuse box by one screw on the left side. It’s a little hard to get to particularly if you have tilt away steering due to the vacuum motor. But with a little patience you should be able to unplug the old relay and unscrew it from the fuse box and then install the new version. My directional arrows now blink but between the stereo and the exhaust I hardly ever here the clicking. LOL