On very cold mornings and days when my truck is outside in the cold, the alternator does not charge until the inside of the cab warms up. The truck runs on the battery only. The dash and dome lights start off OK, but slowly go dim. The gauges eventually die. Radio dies. The heater fan, which I need to warm up the cab, goes slower and slower. I hear beeps from the computer. The idle gets rough and if I let it stall, I have to jump it off to restart. THEN, I hear a click and everything comes back on, as normal. Never does it above freezing. Never throws a code. I've tried a heat gun and a hair dryer to try and blow hot air under the dash, but all that's done is burn my floor mat. I know not to even try and drive anywhere until it warms up, or I'll lose gauges and everything else. A Dodge friend thinks it's the body control module. Like to know what Ford folks think.
98 F150 Lariat 50th Anniversary, 4.6, Auto. Still a great looking, great running truck, except for this.
Thanks for the reply. The "click" I hear when power is restored is definitely coming from behind the dashboard. I will try your idea, though. I Googled "Body Control Module" and it comes up a Dodge component that definitely sounds like it could be the problem (whatever the equivalent component is in Fords). I found a Ford Powertrain Control Module, but no Body Control Module.
The relay I hear clicking is what restores the power, and my guess, connects the dashboard power to the alternator. Before it clicks, the power is drained from the battery completely. Today, I had to connect my portable power DieHard 950 (which is supposed to be used to jump a battery) and leave it connected to give me power to run the heater fan so the inside would warm up. It's definitely related to cold weather (metal shrinks in cold and expands in heat). Could be loose contacts or a cable connection is loose. Called a Ford Dealer. They wanted to throw a new generator on it. I told them they weren't listening. It only does it in very cold weather. Been going on for about 4 years, but it rarely gets this cold here, so I've put up with it.
Now I'm thinking it is the alarm. I was standing outside the truck on the passenger side and inadvertently pushed the alarm button on my keyring. I heard a relay click behind the dash that sounds the same as the relay I hear click when the truck finally warms up. If you ever tried to start your truck while the alarm is going off you know the electrical system is disabled. Still haven't pulled the dash apart. Could use a link for an expert on Clifford car alarms.
I have the same problem. On cold mornings, hit and miss, my truck will not charge. The same sound is heard as yours. It does it randomly, but only on cold mornings. I cleaned all the grounds except one. Had the alt checked, Checked all fusible links. Adjusted belts. Last month, I found a wire that extended from my firewall (wires are red and black) to fuses by battery and connecting to ground at battery (black) and relay on firwall (red). The black one was disconnected off battery. I connected it and two things happened. Suddenly I am getting a battery indicator light at ignition start and no more charging problems. today, a month later, it did it again. As usual a cold morning. It did not charge to work (8 miles). I tried starting it, still no battery indicator light at turning key, and still no charge. I went out there at midday to start. Like magic, battery indicator turned on at ignition and trucck was charging.
I have narrowed it down to either a ground or connection or maybe the trailer hitch wiring. I had tested the wiring at hitch the day before so maybe there is a problem.
My question is "what are the red and black two wires travelling singly through the firewall into driver compartment, under floor mat, and back? Is that the trailer wiring or fuel pump wiring? Or something else? The wires go from the firewall ,cross engine, and end up joining at fuses (fusable link by passenger headlight) and back to relay mounted on firewall (red) and black directly to negative battery terminal? If you answer this, this may be a solution to both our problems.
PS - My radio was taken out yesterday because it is not working. Maybe this is the problem???? Doubt it.
Define the wire i'm talking about and we'll both go from there.
We had both commented about the charging issue recently and I think i may have found your problem.
Next time it charges intermittently, check fuse #30 (coil ignition fuse under the dash in the driver compartment) or 5 amp fuse above it. I found that each time it acted up recently, I wiggle that fuse #30 (push it in tightly) and presto, the problem disappears. There is a little blog online about such a problem and its troubleshooting. Check it out. It is working for me.