So when i turn the truck on on a 19* day like today i get a rapid clicking from the manifold heater relay. The small one mounted on the fenderwell. The switching device for this relay is the computer or SBEC. has anyone ran into this problem before?

 

or a bad relay?

 

Simple test.
Unplug the air temp sensor on the intake, with the key on, if the solenoid quits clicking erratically, it's likely the sensor.
If it continues to click, it's probably the module.

Mark.

 

I did swamp relays. that was the first thing i tried. I also unplugged the temp. sensor and it didnt click, but the wait to start light flashed after 20s which i guess indicates an open sensor circuit. however i dont trust that test since the truck was kind of warm. see it only does it when its cold out. the colder the worse it gets.

 

When it flashed after the sensor was unplugged, it did as it was supposed to, tell you there was trouble in the system.
My '91.5 did that, after I had forgot to plug it in when I swapped the injection pump.

Replace the sensor.

Mark.

 

So i replaced the sensor and i still have the same problem. Are we looking at a computer do you think? Is there any fusible links that could be causing this? Im not too worried about it not starting, it would just be nice to have a little help for those really cold days.

 

So ive isolated my problem to a computer. does anyone know where i can get one? im not looking to get mine refurbished. Mopar still sells them but their back ordered through mid january. I need a 7572 one.

 

PM forthcoming.

Mark.

 

Also interested in where to get a good replacement, not sure which one mine is, and it's dark out so not gonna go look now. But mine has lots of wiring issues and strange things the lights and sensors do. Already had to bypass the OD switch so I can manually engage OD for it. Also does anyone know the proper vacuum diagrams for mine?