Another grid heater thread

[Doubletrouble]

 So in preparation for winter I've been checking and testing some things to avoid issues in the cold. It has been cool enough for the grids to cycle so I thought I would test a bit to avoid later issues.

 I checked for voltage at the grid heaters in the intake horn. I had 10.33v DC. That didn't sound right, why not 12+ volts so I checked at the battery- 12.5 volts (engine not running). Checked at the hot side of both relays-12.5 volts. Then checked grid side of relays-10.33 volts. 

 I'm going to assume this voltage drop at the relays is not normal or acceptable?

 Is this showing the contacts being worn and or cruddy inside the relay? Time to replace?

 Thanks.

[Tractorman]

Just want to make sure - are you performing each voltage check while the grid heaters are cycled on?  This would be the proper procedure.  Also, are you using the same ground point for each test?

 

- John

[Doubletrouble]

Yes sir. 

[Haggar]

If you had the grid heaters on and measured 12.3v on one side of the relay and 10.5 on the other side,  that is a 2v drop through that component.  So 17% of your energy is heating your contacts.   I think that is too much and indicative of the contacts beginning to fail.

 

Leave your grids on and feel the relays, are they too getting warm?   I never got to measure the voltage drop on mine, but eventually my originals got hot enough to distort (melt) the relay bodies.

 

HTH

Hag

[Mopar1973Man]

Could be the cables are corroded too. Do voltage drop test and see if either #1 or #2 leads are failing. 

[Doubletrouble]

I will check and clean the contacts and check voltage drop as well. I'm thinking that these relays are oem so probably wearing out but I also don't like replacing stuff that is good. 

[Mopar1973Man]

Hence why I'm suggestion to do the voltage drop and verify if it the wire, relays, fusible links going bad. Etc. 

[Eric H.]

Mine had tons of battery corrosion on the terminals, including in the crimps and down the wire into the insulation. I eliminated the heater so I didn't need to do a drop test but I bet it was bad.