engine control module

there are several modules that run the vehicle , what is exactly coming on and ir not coming on

All the dash lights come on. horn came on by itself.

i would check the normal things before jumping into modules , check the relay center and fuse box for corrosion , you may have to pull the fuses out one at a time to see if there is anything on the blades

Checked all that already. fuses relays and ignition switch. My mechanic seams to think it's the ECM. Other people are telling me that the computer has nothing to do with the dummy lights on the dash and......

you pulled every one and checked the blades for corrosion ?? if so i would suspect the ignition switch , not the key ,, the electronic part , there was a problem in that year with the switches causing this problem and also corroded relays and fuses

A lot of folks guess that a computer is the problem to many problems. There was a period that computers were troublesome. It is rare to have to replace a computer on many cars these days. It's a damned expensive guess.

I replaced the ignition switch. I swapped the relays for the horn and the starter when that was the problem and it still did it. I checked all the gouds that I could find and cleaned them and screwed them back in. everything seemed fine for a few days then the truck started lossing power. it got progressivly worse untill the truck wouldn't go more than 15 miles an hour. the check engine light came on and I drove it to the nearest shop. They diagnosed it as a bad cat converter. I told them about all the electrical problems I've been having and that they should make sure the converter is plugged like they think it is. they were pulling it back into the garage when all the dash lights came on then I guess the truck started running different.

Running different how? What codes are in the PCM?