Engine/Transmission (1994 - 1998) Heater Grids not working.

[Got Smoke?]

Heater Grids not working *UPDATE* allied relays are here

My heater grids are not working in my new-to-me truck. I have been having a really hard time starting it whens its sat outside in the cold for a while without being plugged in. It usually requires me to hold the throttle WIDE open just to get it started then I have to feather it to keep it alive for the first few seconds.



But I cannot see/hear my heater grids cycling at all. The voltage gauge never drops like it would if my grids were cycling.



So where do I start diagnosing this problem? I know there is a relay for them, but where is it at?



TIA

 

[crabman]

Got Smoke,

The relays are located under the driver's side battery.

If you want to know how to check out the relays and the heater grids, check out the thread by rnolen, "Electrical Problems" in this forum. I posted the step by step instructions on checking out those two items.

The relays are about $70 from dealer and come in pairs.

Good Luck!

crabman

 

[Got Smoke?]

$70 there goes some Christmas money from the BOMBing budget! :{



Thanks, I will check out that thread!

 

[dalton4]

Got Smoke, I've read where owners have replaced the relays with the old style Ford starter relays with good results. I believe you can buy these for about $10 each. So, on with the bombing!

 

[DPinkston]

Got Smoke, I've read where owners have replaced the relays with the old style Ford starter relays with good results. I believe you can buy these for about $10 each. So, on with the bombing!

I considered doing this but one problem comes to mind when using the Ford solenoids. They ground through their mounting. The Dodge heater solenoids are electrically insulated from the mount and ground through the computer. There is 12V going to them when you switch the key on. For simplicity I just went and bought a new pair at Dodge. $65 tax and all.

Danny

 

[JAmos]

Has anyone had any luck buying the relays at a truck parts store for less $$$? I'm going out to test mine this afternoon and was wondering if the medium or heavy duty trucks use the same relays. I have had mixed luck getting parts from a truck shop, but when the part is right, it's usually cheaper. Jordan

 

[QRTRHRS]

Read here.

https://www.turbodieselregister.com/forums/showthread.php?t=1382&highlight=Gridheaterselenoids



On page two, you can find reference to the Stancor #120-902 selelnoids available through Allied Electronics. Somewhere buried in my notes is a thread about making a new bracket to use with these. No matter, it's easy enough to fab. If you look at your stock selenoids, they are perpendicular to the fender well. The Stancors are slightly taller which would make them more prone to rubbing on your battery cables and more. The stock bracket is "L" shaped. Make one "U" shaped then bolt the selenoids to the inside bottom of the "U" so that they lay parallel to the fender. The extra metal will shield them.



I have these in 2-3 years now.

 

[Got Smoke?]

Ok here's a update as well as a new question.



While working the truck today I was glancing at the heater grid relays... . I reached down to check out the 4 little wires (2 on each relay) and the orange wire with the black stripe on one of the relays came right off with me barely even touching it.



Now when I went to place that wire back on the relay it clicked.



So I tapped the wire the wire on the connector a few times and each time the relay clicked. Already had the key on and intake horn off (doing a Gov. lever adjustment) and had a buddy reach up to the heater grids and where still cold.



Can't understand why if the dang relay is clicking then why aren't my grids heating up?

 

[Eric_77]

My grids cycle off before I can feel any heat in them(mounted that is, you don't have them removed from intake tract do you?)



I would check with a amp meter or check the volt meter you will see that cycle back up when the grids shut off.

 

[DPinkston]

Those little slip on friction connectors used on the solenoids tend to lose their grip after awhile and need to be gently tightened up with a pair of wire crimpers. Even though the solenoid may click doesn't mean it is working right. The same thing happened to me. The only way to know for sure is with a test light.

Danny

 

[Jschafer]

If your intake horn was off did you still have ground to the heaters if not they wont heat up ground strap on mine are at the back bolt of the air horn.

 

[crabman]

Link for Tests

HERE

crabman

 

[Got Smoke?]

If your intake horn was off did you still have ground to the heaters if not they wont heat up ground strap on mine are at the back bolt of the air horn.

Went out and doubled checked before posting... ...



I don't have a ground wire anywhere around my intake horn. I don't remember one on my previous 97 either.



Crab man I'm going to use your checking methods but just thought I'd post my latest find and see what people had to say. Thanks

 

[JAmos]

My 95 has a heavy ground wire that comes from the heater grid unit and grounds under one of the intake horn mounting bolts. Just because a relay clicks doesn't always mean it is connecting the higher current circuit, especially if the contacts are burnt, worn, corroded, or all three.



Jordan

 

[Got Smoke?]

Ok guys time to drudge this old post up again.



Thanks to Crabman I was able to test my OEM relays and know for sure they were NOT working. He linked me to JoeBioDiesel's post a while back talking about the Stanco 120-902 relays, and how to mount them. I will include that post a little ways down.



I ordered the relay's on Wed. @ 11:15am, they were $35. 14 to my door and they were here before 10:15 this morning! Oo.



First overall impression out of the box is like everyone else says they do resemble the OEM relays, but I wouldn't say they are alike. I might change my mind once I get the OEM's in my had, but these units seem more beefier than the stockers. I will find out tomorrow when I install them. I will take pictures for everybody, and add any addition thoughts I think need to be know.



Thanks again Crabman.

Hi FF1607,

Here is a link to Allieds search page.

http://www.alliedelec.com/Search. ASP



You want two Stancor relays part # 120-902.



Search by manufacturer part # to find it easiest.

They just came off backorder. I have installed 4 of these in the last month. They all failed the same way. When you triggered them they didn't even click(and they normally click pretty loudly).



If you end up ordering these relays you will need to modify the stock bracket a little bit in otder to make it fit nicely.

I remove the entire bracket.

Bend the tabs at the base of the old relays, the relays will fall apart.

Cut the tabs off with a pair of side-cutting pliers.

File or grind the sides of the bracket where the tabs used to be, gring them the entire length of the bracket.

Bend the brackets on the new relays backwards around the old bracket. Put the bump on the bottoom of the new relays into the depression in the old bracket and they will stay in place nicely.



If you'd rather call Allied on the phone, their # is 800-433-5700.



Good luck,

Joe

 

[crabman]

Got Smoke,

NO PROBLEM!!!

Hope it is/was the "fix" for your problem!!.

crabman