Good evening all. I have been lurking here for some time and finally decided to dive in and see if some of you might have some suggestions as to the problems that have sprung up on my '97 F150.

First off, let me give some truck details. It is a 1997 F150 Lariat regular cab. It was one of the early 97s that were sold alongside the older model in 1996. This particular truck was built in Norfolk in November of 1995 and was purchased in February of 1996. It has the 4.6L engine and all the usual Lariat features plus the tow package.

Aside from an intermittent problem with the cruise control, everything was running fine until about 4 months ago. All of a sudden, the remote keyless entry stopped working, along with the power mirrors, the autolamp system, and the auto lock feature on the power door locks. These items all stopped at the exact same time. I checked the obvious fuses and such with no luck.

About 2 months after that happened, the radio began acting up. This is the factory unit with the behind the seat CD changer. Ever now and then, the radio would not turn on when the truck was started. Turning the key off and on a time or two would fix the problem and everything would be fine for a while. It also started going into tape mode on occasion when the truck was started even though a tape has not been in the unit in years. Hitting the radio button would put it back into radio mode without fail.

This happened 3 or 4 times over about a month or two. Then one morning a couple weeks ago, the radio stopped working entirely and has not worked since. The display is also completely blank at all times, no clock or anything. The buttons do continue to light up when the headlights are on, but that is the only sign of life at all. The fuses under the dash and in the engine compartment seem fine (I think it is 8 and 11 if momory serves).

Anyone have any suggestions on what direction I should be looking with these issues? I was considering replacing the radio with a new unit even before the failure, so that is an option on that one, but I would like to feel more confident that a new radio would actually work and that the problem is not something else.

Thanks for any suggestions.

John

 

I would "meter" all the fuses...even though they might look ok,its possible one or more are intermittent....Check the fuse sockets for corrosion etc.
Check all ground paths especially on the Battery terminals.Check for corrosion on both positive and negative batt terminals.
My term "meter" means to pull each fuse,and read the resistance with an ohm meter.

Does youre lighter/accy plug work?

 

I can give that a shot. Actually as cheap as they are, I might even just go ahead and replace the fuses with new ones. Any suggestions as to which ones should really be checked or replaced? I know #8 in the inside panel and #6 under the hood, but any others in particular I should check? Oh, I did also replace the relay in the inside fuse block back when the problems first started with no luck.

There was no sign of corrosion in the inside fuse block or the one under the hood. There is some slight corrosion on the battery terminals. I recently replaced the battery and gave them a quick cleaning then, but it could be better. The battery was replaced probably 3 weeks before the radio stopped working.

Also, the lighter and powerpoint both work just fine.

Thanks for the fast reply as well!

John

 

Your comment on ground paths did make me think of something as well. I don't know if it is relevant or not, but just in case...

I have an XM satellite radio unit in the truck and have had it for about 2 years now I guess. It uses FM to broadcast, but when it was installed a RF modulator was installed that basically routes the signal straight through the antenna connector on the radio to eliminate problems with finding a clear frequency. Every now and then, especially when it is cold, there was a faint high-pitched whine from the speakers that I would say was probably caused by a ground loop. I had not heard it for a while now, though.

John

 

Hi John,
I wish I could point you in the right direction as far as fuse designation is concerned,but I cant.I can only tell you that my 97 has a TON of factory load center pieces,and any of them could have been be the culprit.
Normally in the case of a radio,there are two B+ feeds....one is constant hot for the radio memory,and the other is switched hot for the primary power.
The constant hot(as eluded to above) usually is on either the lighter circuit,or(in my case) the accessory plug circuit.
Also...most of the "extras" like alarm,and door locks need to be on a constant hot circuit as well.This circuit may.or may not be the same as the Radio memory circuit,but nevertheless should be hot at all times.
Hot of course means Batt voltage..in reference to ground.... The whine you have experienced does indicate either a lack of ground,or lack of shielding in the co/ax from your sat radio....The whine can also be attributed to an open shield(ground) in your factory radio setup as well....Hope this gives some insight as to what to look for

 

sounds like water is getting into the fuse box and causing stray voltage to screw with things.this will usually require a new fuse box, gem module and getting the wind sheild resealed.common problem.remove the 2 bulk head connectors from the rear of the fuse box and inspect the fuse box with a mirror.at the bottom you will see a green corrotion build up.good luck.

 

Would you say this is likely the cause of the radio problem as well?

Any tips on removing those connectors? I'll try and tackle that in the next couple days to see if there is corrosion there.

John

 

the radio messing up is what made me suggst the inspection.there are 2 10 mm headead bolts that secure the connectors to the back side of the fuse box.if you remove the fuse box for inspection you will have to unplug the gem module on top of the fuse box to remove it.they can sometimes be a bear.good luck

 

I just wanted to give people an update.

I was swamped for the past few weeks and have not had time to mess with this any more. This morning, I took the truck to the dealer to have diagnostics checked out on it. Their diagnosis is that there is a wiring problem. They were getting no voltage to the RAP (?) module. They were a bit short handed today and were not able to finish the diagnosis, so I made an appointment to take the truck back to them on Tuesday morning and leave it with them.

What is a RAP module exactly? Also, does anyone know what the general price range on replacing one may be?

John

 

About three months ago I bought my '97 F-150 with 132K on the speedometer from a private individual who had just brought it from Florida, where it had been for several years, to New Mexico where I live. Everything electrical worked on it for the first month or so. Then I noticed that my fog lights and back up lights weren't working anymore. I checked the bulbs and they were OK. I pulled the fuse for the back up light. It checked OK and when I put the same fuse back in the lights started working again. The same thing happened on one of the fog light bulbs. I got some contact grease from the local Auto Zone store, applied it to the fuses and the bulbs and everything was suddenly working again. I can only guess there was some corrosion on the contacts. I have no idea why it developed after coming from a humid climate to an extremely dry one. I would have expected it to be the other way around. Incidentally, I had talked to a mechanic at one of the local garages and he mentioned something about a module but didn't do any diagnostics and was talking way over my head so I had no idea what he was talking about.

 

Well, to close this out, I took the truck back to the dealer on Tuesday and they determined that the RAP module was faulty. They replaced this with a new module and programmed a new key fob for me to work with the new module. This fixed the mirrors, the keyless entry, the auto-locking on the doors, and the autolamp system.

As far as the radio goes, it was diagnosed as simply a failed head unit. I'll take it in this weekend and get a new radio installed at Best Buy or somewhere.

This takes a few items off my 'to be fixed' list on the truck. I still have a lot of nagging issues that need to be resolved, but they are all pretty minor.

This weekend the plan is to replace the spark plug wires. Hopefully that will be another one I can check off the list.

John