Taxa publishes its own troubleshooting sheet for the Mantis, and it is worth reading before you suspect anything expensive, because three of the faults owners report most are ones Taxa already lists with a cause and a fix. The water pump that will not turn on. The roof that leaks. The seal that has stopped sealing.
This guide walks through those three, in the order they tend to come up, and adds the parts side that Taxa's sheet does not cover.
The water pump will not turn on
Taxa's own instruction for a pump that has gone dead is short: check the glass fuse beneath the switch.
That is a different place from where most RV owners look. On a typical travel trailer the pump is fed from a blade fuse in the distribution panel. On a Mantis the protection is a small glass cartridge fuse in a holder near the pump switch itself, and it is easy to walk straight past.
How to check it. Find the switch, find the holder beneath it, and pull the fuse. Hold it to the light. A parted or blackened element is a blown fuse. Read the rating printed on the metal cap and replace with the same rating, never higher. A glass fuse that looks intact can still be open, so test it with a meter on continuity if you are not sure.
If it blows again immediately, you have a short rather than a tired fuse. The usual causes on a pump circuit are a chafed wire where it passes through the floor or a bulkhead, water in the pump's own connector, or a pump motor that has failed and is drawing hard. Our guide to a fuse that keeps blowing covers tracing it.
If the fuse is fine and the pump is still dead, check for voltage at the pump's own connector with the switch on. Voltage present and no pump means the pump. No voltage means the switch or the wiring to it.
If the pump runs but cycles or will not build pressure, that is a plumbing problem rather than an electrical one, and it is nearly always a small air leak on the suction side, a partially open bypass valve, or a clogged inlet screen. Check those before replacing anything.
A 12 V self-priming water pump and its inlet and outlet fittings are the replacement when the motor has genuinely gone, and a tank level sender is worth checking while the plumbing bay is open, because a pump that runs dry against an empty tank the gauge said was half full does not last.
The roof leaks
The Mantis and Cricket roofs lift and latch down, and Taxa's sheet attributes leaks to a specific cause: loose roof latches. Their fix is to adjust the interior roof latches and make sure the fabric, the window toggles and the weatherseal are all contributing to the seal, and to inspect and replace the weatherseal if required.
That is a useful diagnosis because it tells you the leak is usually not a hole. It is the roof not being pulled down hard enough, evenly enough, onto a seal that is still capable of sealing.
Work through it in this order.
- Close the roof and look at the gap all the way round. It should be even. A corner that sits higher than the rest is a latch that is not pulling.
- Adjust the interior latches. They are adjustable for a reason. Tighten the one at the high corner until the gap matches the others, and do not over-tighten the rest to compensate, because that distorts the roof and opens a gap somewhere else.
- Check the window toggles and the fabric. On a soft-sided lift, the fabric and the toggles that tension it are part of the seal. A toggle left undone or fabric caught in the closure is a leak that no amount of latch adjustment fixes.
- Then, and only then, look at the weatherseal. If the latches are pulling evenly and the fabric is right and it still leaks, the seal itself has hardened or flattened.
The test that finds the gap. At dusk, with the roof latched, put a torch inside and walk round outside. Light leaking out is the gap. It is faster than any hose test and it finds the side you were not looking at.
The weatherseal has stopped sealing
EPDM rubber seals last well but not forever. Sun, heat cycling and thousands of latch cycles flatten them, and a flattened seal does not spring back to fill the gap when the roof closes.
How to tell. Press the seal with a thumb. It should compress and recover. A seal that stays dented, feels hard, or shows cracks at the corners is finished. Also look for a shiny, polished line along the seal, which is the compression set that tells you it has stopped recovering.
Replacing it. A self-adhesive bubble-profile EPDM rubber seal is the general-purpose answer for a lift roof, a hatch or a compartment. Fitting notes that decide whether it lasts:
- Remove every trace of the old seal and its adhesive. New seal on old adhesive is bonded to the failure.
- Clean the channel to bare, dry surface. The surface you are sealing is, by definition, the dirty one.
- Run it in one piece wherever you can. Every joint is a potential gap, and the corners are where leaks start.
- Do not stretch it. Stretched seal shrinks back over weeks and opens a gap at the join.
- Latch the roof down on it for a day before judging the result, so the adhesive cures under compression.
Then re-check the latch adjustment, because a fresh, fuller seal changes where the latches need to be.
Dust, which follows the same path as water
If the roof lets water in at a latch, it lets dust in there too, and Taxa owners who use these campers off pavement see dust before they see water. The diagnosis is identical: even gap, latch adjustment, then seal. Our guide to dust ingress on off-road campers covers the compartment and pass-through side of the same problem.
The parts that are Taxa-specific, and the parts that are not
The roof latches, the fabric and the window toggles are Taxa parts, and Taxa's manuals page is the place to identify them. The water pump, the fuse, the seal and the tank sender are not Taxa-specific: they are standard 12 V and plumbing components that many off-road campers share, which is why we can supply them. Our universal parts guide covers what crosses over.
If you have found the fault and are not sure which part fixes it, send us a photo of the old one and your model year. Everything ships from Upland, California.