I have an electrical problem with my 1997 F150 2wd 4.2L. My battery was not charging and the alternator had some bearing noise so I replaced the alternator hoping it would charge with a new one. Well, it does not. The battery base volts are about 12.5 and when itwas started andrunning it has dropped down to about 11.8 over a 5 minute interval.

I purchased the truck the other day and I do not have a history with it but I do know the wipers have only worked for me once and that was momentarily when I started the truck with the wipers on. 2. The pump for the wipers does not work. 3. Relay 1 in the fuse box under the steering wheel clicks when I rev the engine. 4. #3 fuse (25 amp cigerette lighter) is blown. 5. When I turn the ignition to first position the idiot lights are working. 6. It has full instramentation that says everything is fine but the volts.

Can anyone give me information as to where to test with my volt/ohm meter forsomethingor does someone outright know what the problem is.

Thank you for any help.

Ian

 

Since you've done an alt swap, with a tested one? check the mega fuse as well as the mini..

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I checked those three fuses right away when the new alternatorwas not working and they are fine. Admittedly I did not take one of the wires offside of each of the big ones I checked them quickly with the wires on. I will check again and this time I will check for voltage at both ends.

 

The problem was the #3 fuse. According to the operators manual from the glovebox it is for the cigarette lighter. Today I got some fuses for the truck and replaced #3 and I have over 14 volts even with the lights and heater on. I took out the fuse and it dropped to below 12 volts. (the battery base was about 12.2)

I bought a Haynes repair manual for schematics and when I got home it does not have the 4.2L for electrical, engine orchasis,and the schematic that it does have has wrong wire colors.

I am back to the wiper problem and I am looking for information so that I will know what relay goes to what, both under the hood and under the steering wheel.

Ian