99 Tahoe Basic 4x4 DTR module failed RESOLVED

[K7KY]

My DTR diode is kuput. 2 online used DTRs also kuput. Dorman no longer makes this module. I'm thinking to drill out the bad diode and replace it. Removing the old one will demolish it. I need to know it's capacity. I've tested the circuit with a 3A diode. Although the circuit now works, the 3A diode gets warm quickly. Whatever the capacity, it obviously needs the large heatsink. If you know the original diode capacity, it'll be a big help. Thank you.

Thanks for your assistance with the DTR module and the reminder to mark the thread Resolved. I bought a new unit @ eBay for $82.50. Here's an image of the module disassembled. Two diodes in parallel. The thermal potting in the old unit was nearly powder. The diodes would not cool as designed. It appears this was the original unit. I couldn't remove the bracket as the bolt head is nearly touching the heater/ac unit. I don't think the metal tabs that hold the heatsink had be previously bent. If this module lasts as long as the original, it will outlast me...

 

[Joseph Garcia]

Do you have a part number for your DTR module?

 

[K7KY]

Do you have a part number for your DTR module?

Joe... I think Dorman & GM have discontinued this part. Maybe I'm wrong about GM. Meantime, I disassembled the two faulty units. There are two diodes in parallel. Oddly, the schematic indicates the diodes are in series. The DTR module has a 20a fuse (#15). I have some 15a 600v diodes that I may be able to cobble into the heatsink if I can't find an original part. Obviously these diodes run quite hot and a big heatsink is required. I tested the circuit with a 3a diode that quickly got warm.

 

[Fless]

Joe... I think Dorman & GM have discontinued this part. Maybe I'm wrong about GM. Meantime, I disassembled the two faulty units. There are two diodes in parallel. Oddly, the schematic indicates the diodes are in series. The DTR module has a 20a fuse (#15). I have some 15a 600v diodes that I may be able to cobble into the heatsink if I can't find an original part. Obviously these diodes run quite hot and a big heatsink is required. I tested the circuit with a 3a diode that quickly got warm.

I'll ask it a different way. What GM or Dorman part number are you looking for, or are you not sure? You may be able to find the GM part number on www.gmpartsgiant.com by entering your VIN and searching, but don't buy the part there even if it's available. We've seen many complaints about their buying process.

We could ask @915_Tahoe for the part number if you'll give him the last 8 digits of your VIN.

 

[K7KY]

DTR module. Dorman# 704-117. gmpartsgiant doesn't list the module; I emailed them for assistance. I also asked @915 Tahoe and sent him the VIN. Thanks for the guidance. Meantime, I'll try making my own in case none are available. It'll be a learning exercise if I don't need it.

 

[Eman85]

https://www.ebay.com/itm/1327436858...JSkkq/oOaq60lMz2c6BJIGQvU=|tkp:Bk9SR_rHt-XBZg

 

[Fless]

https://www.ebay.com/itm/132743685821?_skw=dorman+car+partsdorman+704-117&epid=657470478&itmmeta=01K875DWFP797W68Y1JWN8BPJ7&hash=item1ee823e6bd:g:Nb4AAeSw6M1osIZC&itmprp=enc:AQAKAAABAFkggFvd1GGDu0w3yXCmi1cnAY1pGIghV2BDH5FFBoL0rWwL2QPXb6fQTLEJBt49xW03g92LNylQfljxBeeBi8voWs0qmtsjbeUbVV3N3D07ynvA1Lj9EVPQ2JARBtDILIJVJIBJmRjsmbqokV8xi4pkKDJ0bsV02uyUijWgWhazIE1BQ/1h1sfQk9eGZhcmCEt77ZWsi0BThD2GlWW9x8iPSSQihjxH4foU8tsTMc4vhICA0yb3MJxk2Lt8UBhkGW4qTqZbzBPlW07oAlJBHeQIbYrRRkiEGSpDgPw9RdlF4gmx+3QIqPb5z9mrFjJSkkq/oOaq60lMz2c6BJIGQvU=|tkp:Bk9SR_rHt-XBZg

If the fitment chart is correct that module is on an awful lot of vehicles. Seems like a UPull or www.car-part.com would have one available.

 

[homesick]

I'll admit that I'm not a fan of all the automatic behaviors in vehicles, so I'm biased here, but...

Why not do it the old-fashioned way? Why not just turn them on, and turn them off? It works and is pretty much foolproof.

joe

 

[Blackcar]

Maybe this will interchange.

Pardon Our Interruption...

 

[K7KY]

If the fitment chart is correct that module is on an awful lot of vehicles. Seems like a UPull or www.car-part.com would have one available.

Thank you. I already tried two used ones from parts pickers @ $30 & $40. Both failed and were refunded. One was clearly dead; one did forward some voltage, but still didn't work. I'll read the new one to learn what the reading should be. The original unit failed intermittently. It would revive by just lifting battery ground for a few seconds. Eventually, that didn't work. Electronics don't tolerate high heat. Disassembling one revealed there's 2 diodes in parallel potted in thermal potting so they're both the same temperature. This unit may have been replaced previously in the life of this Tahoe. I just ordered a new GM part @ $82.50 from eBay. I was hoping to fix it for less, but not this time.
The GM part#: OEM GM 15043231 Diode Daytime Running 2003-89 General Motors Cars Trucks
I found 3 other part numbers that appear to be the same unit. Thanks to all who helped me. I really appreciate TYF

Joe is right about the simplicity of turning the lights on/off manually. My wife likes the auto feature; she's the principle driver. We're just north of the California border and there's a long stretch of Hwy 101 in CA where headlights are required on by law and an routine stop by CHP. It's easy to forget and leave your headlights are on in daytime. Anyway, the new unit should end this thread.

Maybe this will interchange.

Pardon Our Interruption...

Thank you for this tip. I think it's the right part, but I'm reluctant to try another used one after two used ones failed. I just bit-the-bullet and ordered a new one. I appreciate this forum with so many friendly and helpful members. I'll be helpful when I can.

 

[Joseph Garcia]

Be sure to let us know how this works out for you. We'd loved to see the word 'SOLVED' in your thread title, after you get it back together.

 

[915_Tahoe]

I'll ask it a different way. What GM or Dorman part number are you looking for, or are you not sure? You may be able to find the GM part number on www.gmpartsgiant.com by entering your VIN and searching, but don't buy the part there even if it's available. We've seen many complaints about their buying process.

We could ask @915_Tahoe for the part number if you'll give him the last 8 digits of your VIN.

Gm#15043231
Discontinued
But there a dealers that show to have it in stock.