5.3 Thermostat Housing with Temp Ports

[dme922]

Im running a 5.3 out of a 04 silverado and i am trying to find a thermostat housing with temp ports fo my fan sender. If anyone knows where to get one or part # it would be much appreciated

[mongocanfly]

Not sure about the housing your looking (I've not seen one) for but you could use the sending unit hole that would be in the passenger side head ...opposite of the one in the drivers side head...its gonna be metric though..you may have to drill and tap it out..

[dme922]

I used that port for my dakota digital sender but it it ok to just drill and tap the factory thermostat housing?

[mongocanfly]

Your ecm will need a temp reading to...on mine the way I have it set up is..ecm reads from drivers side head sending unit..my temp gauge reads from passenger side head..the ecm controls my fans..do you have this running or are you in the install stage?

[dme922]

I have it running. I am using a painless wiring harness and it has two wires marked fan 1 and fan two but thee fans will not come on with them ran to these wires

[LEEVON]

Top of the water pump is easier...I have one there and in the head. I have never seen an LS t-stat housing with temp sending units or bungs/ports.

[mongocanfly]

You may have a problem with your ecm program..some ecms are only setup to run one fan...mine was that way and it wouldn't work either..I had to get it reprogrammed to run 2 fans and now its fine..I used a psi harness and fan 1 and fan 2 wires go to a set of psi relays..each relay goes to a fan..how did you have yours setup? those water pump housings are very thin...I ran my steam port that way..the original pump was thicker..I had to replace my leaking pump and the new one was only about half as thick as the factory one was.

[dme922]

I have two relays for my fans and i was running the sender wire from each to the fan 1 and fan 2 or the harness

[ls1nova71]

How did you have them wired? The PCM sends a ground signal to the relay to turn them on, was that how you had it?

[dme922]

I had the fan relays gray wire ran to fan 1 and fan 2. The guy that programmed my computer said it was set for the fans to come on at 205 and off at 190.

[mongocanfly]

Although mine is psi this is how mine is hooked up.. one relay setup separately for each fan..on mine fan 1 is set to come on at 175 and fan 2 comes on at 185.are you trying to run both fans from one relay and did you get a wiring schematic? On the relay you should have a constant 12 volt to relay power..a switched 12v power...a wire from the ecm (fan 1 or fan 2)...and a wire going to the fan..and then the fan should be grounded...you should have 2 circuits setup like this..one for each fan separately.

[dme922]

Im running two relays. Im pretty sure that is how i have them wired. I will be getting my truck back tomorrow and i will double check everything and post some pics.

[mongocanfly]

Im guessing you checked the fuses and made sure your fans do work .i checked my fans with jumper wires to the fan wires to verify they worked.if you wiring checks out I would have to think ecm...my guy set mine initially and said it would work but turned out it didn't..he had to go back in and set it back up for dual fans (he said it was a programming flaw) at first on mine fan 1 would barely turn and fan 2 did nothing..after he fixed it I've had no problems..

[dme922]

Yes the fans work great. Im starting to think ecm.

[mongocanfly]

Ls1nova might have a better answer than me..but if the ecm makes the ground for the relay (and now I'm just guessing ) if you remove the wire from the ecm to the relay and make a jumper wire from the ecm side of the relay and take it to ground the relay should engage and fan should run when you turn the switch on..again I'm just guessing but if so that would prove you have ecm issues,,,, I think

[dme922]

Im pretty sure thats what we did so i could drive it to the upholstery guy. Right now as soon as i turn the key on the fans start running.

[ls1nova71]

Originally Posted by mongocanfly

Ls1nova might have a better answer than me..but if the ecm makes the ground for the relay (and now I'm just guessing ) if you remove the wire from the ecm to the relay and make a jumper wire from the ecm side of the relay and take it to ground the relay should engage and fan should run when you turn the switch on..again I'm just guessing but if so that would prove you have ecm issues,,,, I think

This is exactly what I was getting ready to suggest! It is the quickest way to verify the wiring without a scanner that you can command them on with. like mongo said, unhook the PCM connectors from the PCM, turn the ignition to "on", then find the fan1 and fan2 wires in the PCM connectors, and try grounding them one at a time. If the fans don't come on, you have a wiring issue, if they do come on, either you have a programming issue, or the truck hasn't reached the temperature needed to turn them on.