I've had my gauge installed for a few months, and all of a sudden I noticed the gauge needle would start to jump around. Seemed primarily when I would brake (originally thought maybe fluid sloshing around or something). The temp reading would seem to be normal, but most often would jump up/down to a different temperature while braking and then back to normal while braking again. So I was sent out a whole new transmission gauge assembly from Isspro. At first I installed just the new gauge, control module, and temperature sender (not the cable going to gauge or cable going to sender) but the gauge would still jump. What was odd is one time I had my truck in park (I think the engine was even off but key on) and I would pump the brake and I could see the needle on the gauge move as I pumped the brake. After this, I installed the cable that runs to the gauge itself. Drove for like 4 days and it appeared to be OK, but then I noticed it jumped a couple of times yesterday (haven't been able to repeat the fluctuation in park like before).
So here is some other info or concerns that I'm wanting feedback. Around the same time (not sure how long after when I noticed the gauge jump) I installed a used 6.0 transmission cooler (did my own flush as good as I could), and installed a Tekonsha P3 brake controller (just a plug n' play wiring harness, no actual wiring required). Here is my biggest concern, when I installed the 6.0 cooler I plugged the ends of the hoses with balled up painters tape to prevent any dirt/debris from getting in the lines as I ran them. I'm pretty anal/ocd when I work on things. So I'm pretty dang sure I pulled out the tape before installing all lines and fittings. But since the gauge fluctuation thing, there is a small part of me that worries maybe I forgot one. But here is the thing, the truck drives and shifts just fine, and it doesn't overheat. I'm leaning towards an electrical thing due to things mentioned above, but would like to get feedback.
Could a blocked fitting (from my tape) be causing my gauge to act as it is (but wouldn't I notice a problem with my tranny shifting or overheating)? I have even towed my trailer since then with no issues other than my gauge needle jumping (haven't noticed anything with my stock transmission gauge on the dash). Or is it likely something with my brake controller (again, no wiring involved, it just plugs in with a harness)? Also, there seems to be no rhyme or reason when it starts to act up (other than it seems most often when I brake - I thought at first it might have just been fluid sloshing because of the sudden stop in momentum, but just don't know whether that is even really possible).
Sorry for the long message. Just trying to put my mind at ease that it probably isn't due to my cooler install, and to find out what the likely cause might be. Any help appreciated........