No Power

[PedroR]

on my 96 rd when i turn the key on in the morning there is no power (battery gauge, fuel gauge, no fan, no jake brake, etc) but after about 30 minutes everything comes on and works fine for the rest of the day, i get to the yard and stop the truck wait 20 to 30 minutes and theres no power again.

any idea of what the problem might be, thanks in advanced

[HK Trucking]

Accessory relay not energizing right away when you turn the key on?

[PedroR]

Yea, I tried swithing the relays around but had no luck .

[HK Trucking]

Yea, I tried swithing the relays around but had no luck .

The relay I'm referring to is that one that looks like an old type ford starter solenoid, if you take the top dash panel off (the panel where the ashtray is) it will be down in there toward the right.

If you replace it, be sure to use a constant duty type, as some solenoids look the same but are only rated for intermittent service and will burn out quickly if used for constant duty.

Best to just get the proper relay from Mack.

Also, check that the cab is properly grounded. Years of corrosion could be causing a bad ground.

To test, clamp a temporary jumper wire from the negative bat. terminal to the cab (not to the door, but the cab itself) and see if this corrects the problem. If so, then run a permanent ground wire to the cab.

[PedroR]

thanks HK thats exactly what it was, went to mack got a new accessory relay and $34.00 later problem was solved