The 74 started doing something strange the last time i drove it. When it got hot it would not crank over with the headlights on. I can let it cool off and the it will start. The hotter it gets under the hood the worse this problem is. I think i have a a poor connection some where in the harness. Has anyone else run into something like this?
for some clarification. The starter will not turn when the car is hot and the headlights are on. I can jump across the starter relay and crank the car up.
Sounds like the selonoid is getting hot and failing when heated up.... If it starts when you cross the selonoid and not with the key, first thing and prolly cheapest to replace would be the selonoid switch
It could be possibly a messed up cell in your battery (this is a long shot) but with everything hot and the lights on you may not have enough amperage to draw the relay in the selonoid closed to make contact and work the selonoid switch. By bypassing that you have enough to crank the starter just not enough to do all 3, Lights selonoid and Starter. told you it is a long shot but it looks good on paper
If it starts fine with the engine warm and lights off, but refuses to crank with the lights are on then you probably have a combination of things that are wrong. First, check, clean and tighten all your ground wires - including the block and chassis grounds. The block grounds should be the same size as the battery cables. The negative cable should ground to the frame or the block and the other ground leads need to be big enough to handle the loads. Next, check the capacity of your battery. When the engine is warm, and the lights are on, crank the engine with a volt meter connected to the battery. If the voltage at the battery drops below 9.5 volts then your battery is too weak and you need to replace it. If the battery voltage stays above 9.5 volts then start adding ground wires between the engine and the frame. Use #4 AWG wire and sand the connecting points on the engine and frame until you get shiny metal. Bolt the ground lead tightly and then paint it to keep out water and corrosion. That should fix it.
thanks for all of the suggestions. I have checked the battery when hot and it is ok. I probably will go ahead and replace the relay just because it is cheap and if it does not fix the problem i will start inspecting the wiring.
May be a stupid question here, but why do you crank your car with the lights on? That puts an additional strain on the battery, I would think. Just an observation. True enough something else may be wrong.
