Grid heater not working

[rstorrey]

97 2500 135K stock 5.9
think my grid heater is no longer working because the volt meter doesn't indicate the heavy draw it used to while the "Wait to Start" light is illuminated. Still starts but w/ a puff of black smoke. Wondering if its the grid heater or a solenoid? Going to look into it this wknd.

 

[fest3er]

Most likely the solenoids, but it could be wires, PCM or the engine's manifold temp sensor. Find the control lead that is the ground; you should be able to jumper 12VDC to the *other* lead to see if the relays activate.

After replacing with stock relays twice in four years, I replaced mine with Stancor relays back in October 2001. They're *still* working well. See http://murent.us/dodge-heater-relay/ for what I did.

Unless you live where temps get below 10°F or so , the engine will start very nicely without the intake heaters. If the exhaust is black, all is 'well'; if white, that's unburned fuel and heat is needed. I put mine in gear and bring the RPM up to 1100 or so for a minute or so 'til the engine is smoother. Adding cetane boost should help starting; I use 8 oz. of Stanadyne treatment (cleaner, anti-gel, cetane boost) plus 8 oz. of pure 2-ethylhexyl nitrate per tank of fuel. (I'm still looking for a 'better' cetane boost; there is a chemical that is supposed to be noticeably better.)

 

[rstorrey]

thanks for the post. I'll start w/checking for (v) at the heaters. Solenoids and heaters are stock so I won't be surprised to find the solenoids failed.
I use 7 oz Stanadyne & 9 oz Power Service every tank of fuel.
Thx again.

 

[GAmes]

Slightly nit-picky, but they are relays, not solenoids. I replaced mine with White-Rodgers about a million miles ago, then wired the grounds to a toggle to take the PCM out of the circuit. https://www.waytekwire.com/item/75566/
Be glad yours are stuck open. My first set stuck closed while my truck was in warranty and ruined the batteries while my wife was shopping. She was out of state. The dealer there charged her for a pair of batteries and didn't clean the acid out of the engine bay.

 

[fest3er]

Slightly nit-picky, but they are relays, not solenoids.

Syntax Nazi. Right. They *are* relays. But they use solenoids as actuators. Pbthpbthpbthpbthb.

 

[ofelas]

I believe fest3er and GAmes use the 15v/21ohm 120-902/75566 relays, rather than the 102-901/75565 12v/16ohm OEM spec relays that Geno's sells?

I use the same White-Rodgers 120-902/75566 that Gary has, not a lick of trouble; and they get worked well from Oct-May every year.

 

[fest3er]

Right. I chose the 15VDC because (1) the charging system often runs at 14.8V, (2) the relays are fully engaged at a lower voltage, and (3) the slight extra margin of safety can't hurt. 17 years and they still give a pleasant 'Tock. Tock.' when they disengage.

 

[DavidC]

Syntax Nazi. Right. They *are* relays. But they use solenoids as actuators. Pbthpbthpbthpbthb.

Technically from an electrical standpoint they are contactors. Relays have a common, normally open and normally closed usually rated at 10 amps. Contactors make or break a circuit and you have L1, L2 etc. on one side and T1, T2 on the other and come in varying amp ratings. Relays are capable of sending the circuit from common to normally closed (deenergized) common to normally open (energized) or other creative combinations.

Dave

 

[KATOOM]

This may hopefully help... http://dodgeram.org/tech/dsl/troubleshooting/Maniford_htr.htm