For about 2 weeks now Ive been having this happen to the cluster. When Im driving the gas and temp guage go down to zero, the SECURITY light comes on, the airbag light comes on, and the ABS light also comes on. I think its the alternator thats going out, but the guage for the alternator stays put. Ive checked all my grounds and everything is cool. I have no Idea wtf is going with this thing. What do you guys think.

 

weid i tell you. almost sounds like a PCM issue. does the truck run any different? set any codes? been in alot of water? if you think it is the alternator, check it at the charging lug on the alternator itself and make sure you aren't getting over or under voltage and also check to make sure that it isn't throwing out a little AC instead of DC.

 

the truck runs the same as always. no codes, and no water. how do you check the alternator for ac or dc. I'll check the lug . any other possibilities. thanks.

 

Yeah it really sounds like a PCM problem because when I reprogram my PCM it goes all crazy like that? Hope you get it figured out.

lator

Yellow

 

Buy a multi-meter if you don't have one. You can get one at a parts store for cheap,nowadays. Put it in DC-volts...red probe on alt. lug,black probe on ground...normal is about 13.5 to 15.5 volts with engine running. If you see 17 or 18 volts, turn it off because the voltage regulator part of the alternator is bad.

I changed a alternator on a Mazda that was shooting up to 18v at times and you could see the head lights go brighter when it did it. Your is running good so the alt/reg is probably ok but it doesn't hurt to check it.

You also can connect the volt meter probes to the battery...red pos.,black neg. and monitor the alt/reg since its output goes to the battery. Put the meter in AC volts if you want to...not sure but any AC reading should be very low...less than a volt.

If you've never used a meter get someone to help you until you get familiar with it...they are easy to use.

 

I had this exact problem. It was caused by a loose ground connection. There are 3 grounds wires on the back of you cylinder head. One of them could be slightly loose. 2 are bolted down together on the driver side head and the other is on the passenger side head. You can stick your hand back there and feel for them. They're held by a 15mm bolt. Hope it's as easy of a fix you as it was for me, good luck.

 

Ill check the grounds again today, and I have a multimeter so Ill check that today after work. thanks for the help guys. If this dosnt solve the problem, might one of you guys have a 5.3 pcm for sale?lol

 

the AC you will read will be minimal, it will just tell you if the rectifier is failing in the alternator.

 

Thanks. Ill Check The Grounds As Soon As It Cools Down. Thanks For The Help. Later

 

I Think I Got It. The Two Bolts That Hold The Plugs That Go To The Pcm Where Loose. I Tightened Them Up, I Hope This Solves The Problem. Thanks For All The Help.