Temp sender location - 250 I6 integrated head

[mikentosh]

Hi all, wondering if anybody has a photo of the coolant temp sender location on a 1977 250 I6 motor?

I noticed the other day that it appears I have two senders on this motor, wired in parallel. One is in the side of the head, and other is in the thermostat lowerhousing. The new ‘79 gauge I just put in looks to be showing the correct temp (needle is on halfway mark during regular driving). Never seen this before, am I missing something here?

[Palf70Step]

My 81 only had the one on the thermostat housing that runs the gauge. I don't think I have ever seen the one in the head like your picture. Must be part of a Cali pollution configuration.

EDIT: Just did some reading. I imagine yours is idiot light on the dash. Supposedly if you have just gauges its the one wire to the thermostat housing (like my 81). If you have the idiot lights instead of gauges it uses your configuration. The part in the head runs the lights from the sound of it.

[mikentosh]

It’s quite possible this truck came with a non-gauge cluster. I’ve noticed a couple of other hacky things, like it having the narrow manual shift brake pedal arm despite currently having an automatic trans behind the I-6.

However your post did make me think to look up the ‘77 wiring schematics and that didn’t help to clear it up at all...it looks like two temp senders in the diagrams as well. I can see that coming out of the dash side there is two wires, one of which isn’t used for gauge setups (35A grounded to the ignition switch).

Oh well I guess I’ll leave it as is since it appears to be working great.

[mikentosh]

Just for more confusion I took a look at the ‘82 wiring diagram and it’s got two of them as well wired slightly differently, but one is called “Metal Temp SW”.