Instrument Cluster Issue

[Iant62]

Hi all,
I hope someone can help me out.
I recently bought a 1970 F100 - it’s great mechanically, the only issue I have with it is the speedo doesn’t work, and none of the instruments or lights in the instrument cluster worked, except the turn signal lamps.

Fuses were all good, so I figured it was the printed circuit &/or the IVR and replaced both.

Now, when I plugged it up, the left turn signal lamp comes on, and dims when the headlight switch is turned on, and blinks (goes dimmer) when the left turn signal is on. The right turn signa does not work at all, nor any of the other lamps.

What did I do? I confirmed the printed circuit I bought from Dennis Carpenter is a D0TZ-10K843-A

Any pointers appreciated
Thanks
Ian

[Iant62]

Update to this post.

I spent the day troubleshooting, and eventually tore the instrument cluster down and rebuilt it, and it works. Well, it works as well as it did before. The turn signals work, the ammeter works, but no fuel, temp or oil pressure. But that is for another day.

Still have no idea what I did wrong.

Ian

[basketcase0302]

Iant62
Update to this post.

I spent the day troubleshooting, and eventually tore the instrument cluster down and rebuilt it, and it works. Well, it works as well as it did before. The turn signals work, the ammeter works, but no fuel, temp or oil pressure. But that is for another day.

Still have no idea what I did wrong.

Ian

That's typically gonna be the IPVR here's the troubleshooting tutorial:

http://fordification.com/tech/fuel-sending-units.htm

[WAM]

Hello basketcase,

This was a great read/tutorial, and very educational. I am referencing "The Basics" and Fig.6 in particular that address the instrument cluster.

I have a '77 F250 custom, 400, manual 4-speed.

Instrument cluster backing was crumbled.

I replaced it, reinstalled printed circuit, bench tested gauges and bulbs prior, but not of the gauges, or lights, work.

I was wondering if the IPVR (is it still a 5-volt pulse on the '77?) would be a good stating point on my year of truck, and if the testing protocol would still be the same?

[basketcase0302]

WAM
Hello basketcase,

This was a great read/tutorial, and very educational. I am referencing "The Basics" and Fig.6 in particular that address the instrument cluster.

I have a '77 F250 custom, 400, manual 4-speed.

Instrument cluster backing was crumbled.

I replaced it, reinstalled printed circuit, bench tested gauges and bulbs prior, but not of the gauges, or lights, work.

I was wondering if the IPVR (is it still a 5-volt pulse on the '77?) would be a good stating point on my year of truck, and if the testing protocol would still be the same?

I should be able to answer that question but honestly it has been too many years since I owned a dentside with the PRINTED CIRCUIT BOARD.

But one way to test that theory you have is to unplug the harness/test for 12 volts with a VOM (before turning on the headlight switch) / then test all the pins on the harness again with the headlight switch turned on. I'm pretty sure the printed circuit board also used an IPVR to drop voltage to around 5 VDC but not certain.